Depths of Madness

I’ve said it before, but it’s probably time to say it again.  The most likely explanation for human homosexuality is that it is caused by some pathogen.  It’s too common to be mutational pressure (and we don’t see syndromic versions, as we would in that case), it’s not new, identical twins are usually discordant (~75% of the time), and it’s hell on reproductive fitness.  There is no way it is adaptive: the helpful gay uncle notion, group selection, compensating advantage in females, etc: these range from impossible to bloody unlikely.  It doesn’t exist in most hunter-gatherers: you have to explain what it is you’re even talking about when you ask them.  Presumably with diagrams.

As for Freudian explanations, exotic-becomes-erotic, etc: just reading the social-science literature on the subject is enough to make you wonder if the human brain really does exist to cool the blood.

A fair number of the smarter people interested in the subject agree with me.  Not that they think it proven, but they agree that it is the only theory out there that makes any evolutionary sense.  Bill Hamilton thought it made sense. So does Alan Grafen.  Mike Bailey thinks it more likely than any other explanation tendered thus far.

My model – not the only possible  model based on a pathogen,  but reasonable  – leans on a couple of natural examples.  One is narcolepsy.  We now know that narcolepsy happens when a particular kind of neuron, concentrated in a little region in the hypothalamus, somehow gets zapped.   99% of narcolepsy cases happen in the 25% of the population that has a particular HLA type – which suggests that something, probably a virus, triggers an overenthusiastic immune response that zaps a neuron subpopulation that produce a particular neurotransmitter (called hypocretin or orexin) that regulates appetite and sleep patterns.  And it doesn’t do anything else: narcoleptics aren’t stupid. You can compare narcolepsy to type I diabetes or Parkinson’s disease. Suppose there’s a neuron subpopulation that  performs a key function in male sexual desire:  wipe out that subpopulation, and Bob’s your uncle.

Another is toxoplasma, which we now know changes mouse behavior in ways that increase a mouse’s chance of being devoured by a cat, the definitive host for toxo.  Infected mice are attracted to cat urine, while uninfected mice avoid it.  In fact, in infected mice,  cat urine apparently triggers activity in neural pathways involved in sexual arousal. Microorganisms can reprogram sexual attraction in mammals.

I have had people complain that I’m neglecting the social aspects  of homosexuality, what it means, how people think of it.  Let me tell you a story.  In certain parts of west Africa,  boys are expected to start menstruating around age 14.  And they do,  sort of:  you  start seeing blood in their urine.  When that happens, there’s a big ceremony, everyone says ‘today you are a man’.  Whatever.  The thing is, that’s about the time they put the boys into the flooded rice fields, where they’re exposed to schistosoma haematobium, which causes urinary schistosomiasis.  It’s bad for you: it can impair growth and cognitive development in  children, reduces productivity,  and is a potent cause of bladder cancer over the long term.

Our explanation of male menstruation as urinary schistosomiasis must undermine these people’s traditional culture. Eliminating schistosomiasis would undermine it even further,  just as the rubella vaccine dealt a heavy blow to deaf culture by cutting the number of congenitally deaf children in half. .

Isn’t that just too damn bad.

P.S.  The title comes from the coolest response to this hypothesis I’ve ever received, from some inspired fool in New Zealand: “And descending into the most disturbing depths of madness and the most depraved abuse of science yet conceived, we will even be told that homosexuality is caused by a virus or a bacterium. “

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315 Responses to Depths of Madness

  1. billswift says:

    Off-topic, but have you noticed the extreme anti-evolution bias many health food nuts (on all sides) have. Most recently, the popular claim that sucrose/fructose is toxic because of the way it is processed in the liver. Sucrose and fructose are the most common and sweetest of the natural sugars, claiming that we have evolved to like something that is toxic, when there was no need to evolve a “sweet tooth”, is just plain ignorant.

    • anon666 says:

      The development of a sweet tooth would make us more likely to eat fruit with its many vitamins and minerals prior to mass produced candy and soda.

    • lokkes says:

      Regardless of what you think of the fructose argument, the notion that it is somehow framed in an anti-evolutionary way is just bunkum. On the contrary, the standard fructose-overload story is generally told as a story of human evolution, with sweetness being highly attractive because fruit (the common source of fructose before refined sugars arrived a few hundred years ago) was scarce, seasonal and nutritious.

      As with all things (almost), it´s the dose and concentration that´s at issue. Drink too much water, and you die (Google ““Hold Your Wee for a Wii”). Yet water is essential for life. Dose, dose, dose.

      An apple and a Big Gulp (or four big gulps a day) are not really similar regarding fructose load and concentration, at all. Yet our senses and metabolism are calibrated for the apple, not the Big Gulp. Etc, etc.

    • e says:

      Refined sugars do not occur in nature. We have not evolved to eat them.
      The sugars found in plants are not refined. We evolved to eat them, and they are healthy.

  2. B says:

    Questions:
    1) How come there aren’t higher infection rates? If it’s because of varied immune response, you’d think there would be at least pockets of highly inbred people who were all susceptible.

    2) What other common diseases (except for disfiguring ones like leprosy) elicit such a revulsion in the unafflicted? BTW, note that this revulsion, if not instinctive, is at least very old, going back to the giving of the Torah if not earlier.

    3) What, if any, is the evolutionary point of homophobia? Presumably, if homosexuality is caused by a pathogen, it’s not directly infectious-you can’t catch gay from getting sneezed on, and most prison homosexuality is temporary, with those partaking going back to being heterosexual behavior on release (or so I’ve heard.) So, what’s the point of revulsion?

    • Ian says:

      Men express much more hostility towards male homosexuality than women do. Lots of women like to have gay male friends.

      • B says:

        Gay friends are one thing. Ask a woman how she’d feel if she found out her husband had engaged in homosexual activity before marriage, or if her sons turned out to be gay, and you’ll get a different response.

      • Ian says:

        I just have. One the first point, she says that her husband wasn’t really gay, but that he just hadn’t found the right woman.

        On the second, she says she’d still love them, but would miss not having grandchildren.

      • Abelard Lindsey says:

        Male hostility towards gays is something I’ve never understood. I always look at the world opportunistically. More gay me means more women available to me. Perhaps homophobe men don’t have an opportunistic view of the world.

    • Anonymous says:

      >What, if any, is the evolutionary point of homophobia?

      1) You might be able to browbeat your gay child into holding his/her nose and making a baby with if you’re homophobic. If you are accepting of his homosexuality, your chances of having grandchildren from your gay child are slim to none.

      2) Because of the natural promiscuity of men, gay men tend to spread disease if their sexuality is unrestrained. You may have heard of the HIV virus, which probably would have been of negligible importance outside of Africa if gay lib hadn’t happened. Tuberculosis was thought to be on the way out before its AIDS (therefore gay male) driven renaissance. Even before the AIDS epidemic, liberated gay men in the 70s were spreading other diseases. Imagine what a disaster that would have been in the days before antibiotics.

      Here’s an article about a “clap doctor” who treated gay men in the 70s:
      http://www.virusmyth.com/aids/hiv/bnclapdoctor.htm

      • Abelard Lindsey says:

        I know a gay who was sexually active in the late 70’s. He told me the same stories about the rampant infectious diseases that gays were getting at that time. When SIV was discovered in 1978, he stopped being promiscuous and tried to convince all of his friends to do the same. They all shunned and ignored him. They were all dead by 1984.

      • AlfredCairns says:

        “Even before the AIDS epidemic, liberated gay men in the 70s were spreading other diseases. Imagine what a disaster that would have been in the days before antibiotics.”

        In the late 1970’s, I had an English gay friend who was incredibly promiscuous – 5 different men per day sort of promiscuous. I asked him how he avoided sexually-transmitted infections. He told me that he had antibiotics as a prophylactic.

        My friend was one of the first to die from AIDS in London. He was the first president and founder of the Cambridge University Gay Society. I saw his photo on the cover of the Sunday Times Colour Supplement. They interviewed him about his “unknown disease”. He ranted on about “useless doctors”. Nowhere in the interview was it mentioned that he was homosexual and hugely promiscuous. He must have infected 100+ other men IMHO.

    • gmariamen@comcast.net says:

      As I’ve read Cochran explain it, there are all sorts of pathogens that seem to live in a symbiotic relationship with us, in our gut, say, w/out appearing to do damage ( course, if you read some germ theory –Ewald, Cochran, and others –you being to wonder how many germs really aren’t harmless over the long term). As GC has pointed out many times, the polio virus lives in the gut of a fairly high % of the human population, yet only a small % are ever affected by it. There must be myriads of pathogens that behave similarly.

    • gcochran says:

      Stomach cancer is mostly a consequence of h. pylori infections, at least in those populations where h.pylori is common – most third word countries, and in the recent past, everybody. Those infected had a 1 to 2% risk of stomach cancer. Why wasn’t the risk higher? For that matter, why wasn’t it lower? I’ve heard your question before and it’s never made much sense to me.

      Homophobia is a stupid word. Homoaversion would be better. I don’t know if it’s innate or learned.

      • B says:

        Phobia, aversion, whatever. Point is, it’s weird to have an aversion to a disease if its pathogen is ubiquitous. What’s the point?

        Is there an evolutionary advantage to letting h. pylori colonize your stomach? Is there a conceivable evolutionary advantage to letting the presumable gay pathogen colonize you (as long as it doesn’t actually turn you gay?)

      • TWS says:

        I have to agree here. I am no more scared of homosexuals than I am of anyone else. I am disgusted by their sexual practices however. There is a huge ‘ick’ factor here. Plus, I am worried about overtly homosexual teachers/boy scout leaders/priests etc. Anyone who has a position of trust and access to young children should not be part of a culture that has no problem with man-boy relations.

        Like men who got women pregnant in the past, homosexuals should have to ‘take one for the team’ and avoid unsupervised contact with children. They are much more likely to molest children.

        • Kory Stone says:

          TWS I hope that since you are replying to a blog on scientific theory that you are at least literate. Please read evidence based information on homosexuality, and not stand on unfounded beliefs. Gay men are actually less likely to be pedophiles than their straight male counter parts. I believe your statement about how gays have no problem with “man-boy relations” is grossly misinterpreted! There are those in the gay community that have attraction for older and or younger adult men this doesn’t include minors. I can understand how homosexual sex can be disgusting to heterosexual people because I find heterosexual sex very disgusting myself. I also want to add that pedophilia is not a sexual orientation based issue, Pedophiles whom are straight in adult consensual sexual relationships often abuse young boys. This is because they see the child as sexually ambiguous. You are making yourself look and sound extremely ignorant by making the statement that “They are much more likely to molest children.” meaning gays.

          • lcs says:

            Then why all the obsession with ‘twinks’, who clearly are intended to emulate underage boys. By the way, the reason heterosexuals find homosexual sex disgusting is because it IS disgusting. Your opinion of heterosexual sex is irrelevant.

            • Ethan says:

              As a “twink” myself I can tell you that gay men are not obsessed with twinks. They are mostly interested in muscular and masculine adult males. LOL I wish they were obsessed with twinks. Twinks are considered somewhat of a joke, are made fun of for being ‘skinny’, and tend to only get interest from a smaller segment of the gay population. I could ask the same question: why can I look cross culturally and find straight men who are “obsessed” with youthful women? Because men evolved to like fertility.

          • saintonge235 says:

            Why would men that are straight in adult relationships abuse boys? DUH! They’re in the closet.

            A man who abuses male children is gay or bi. If he was straight, he’d be abusing little girls.

            But gays are human beings, so of course they believe in magic. Call gay child abusers “straight” and they are!

            “Oh, life is a glorious cycle of song,
            “A medley of extemporanea;
            “And love is a thing that can never go wrong;
            “And I am Marie of Romania.” — Dorothy Parker, 1937

            • kek says:

              The fact that gays think that argument works is just demonstrative of the same prison logic that only the bottom is homosexual… the same argument they claim “homophobes” use (lol)

      • Dale says:

        I don’t have the reference and I don’t know if you’ve seen it, but in the mean time there’s been research on homoaversion (“homophobia”), and it turns out to be significantly heritable, the number 0.37 sticks in my memory. Indeed, it’s more heritable than (male) homosexuality.

    • whatever says:

      “How come there aren’t higher infection rates? If it’s because of varied immune response, you’d think there would be at least pockets of highly inbred people who were all susceptible.”
      – Spartans.

    • IsTruthEverUgly? says:

      I wonder if male homoaversion developed as an predisposition to augment the defensive strength of communities. Perhaps in primitive times, having visibly effeminate, passive men walking around one’s village invited attack from raiders and hostile neighbors. Scouts sent to check a potential target would qualify homosexual men as less ferocious and able in physical combat. A village hosting homosexual men would be judged more poorly defended and therefore a more tempting conquest. Homoaversion might have developed to quell expressions of effeminate behavior and banish those males unable to conform. The community that projects a strong defense is likely to be left alone more often and so produce more successful offspring.

      I got this idea a while back while reading an article about perpetrators of gay-bashings. Several of these men were interviewed while incarcerated for more or less random attacks against perceived gay males. The perpetrators supposedly experienced high levels of homoaversion focused on the gender-nonconformity of their victims. One odd item I recall was their frequent report of feeling “unsafe” around homosexual men, although they reported no actual fear of their victims. Perhaps, on some subliminal level, they sense danger witnessing a male exhibiting feminine behaviors.

      • chozang says:

        Maybe. There’s always a danger in taking self-reporting on face value (e.g. Dunning-Kruger). I think it’s more likely that they’re just establishing dominance over weaker males. There’s also a danger of being accused of or mistaken for being homosexual, as this would tend to make a male less attractive to females.

    • RES says:

      I’m going to guess here that an evolutionary revulsion could be based on the disease spreading nature of anal sex, and another cause could be that most gay men tend to be fussy. Men tend to find fussiness in other males annoying although will put up with it in women. There could be evolutionary reasons for male antagonism toward effeminacy.

  3. Sean says:

    You might get fewer (or more) responses like the one from NZ, if you make something clear: Do you currently believe that a pathogen responsible for causing homosexuality is spread by homosexuals?

    • gcochran says:

      I don’t know. It looks unlikely: there would have to a whole lot more cases of boys being molested in childhood than I know of.

      • JayMan says:

        Interestingly, homosexual men are more likely to report having been sexually abused as children.

        • Jacob says:

          Although the authors found that men with histories of childhood sexual abuse were more likely to report ever having had same-sex sexual partners, they did not find any “significant relationships between childhood physical abuse or neglect and same-sex sexual orientation in adulthood”; neither men nor women with histories of childhood physical abuse, sexual abuse, or neglect reported more same-sex sexual partners in the previous year or same-sex romantic cohabitation compared to men and women without such histories. The authors of the study speculated that “sexual abuse may result in uncertainty regarding sexual orientation and greater experimentation with both same- and opposite-sex relationships,” but may not affect ultimate sexual orientation. In other words correlation doesn’t equal causation.

  4. Speaking of the depths of madness, if homosexuality is caused by a pathogen, wouldn’t it be possible to weaponize it?

    Scenario: Most of the high-status positions in a certain society are held by members of demographic group Alpha. Most of the population belongs to demographic group Bravo. There is little love between Alpha and Bravo. Furthermore, Bravo has higher total fertility than Alpha. Some guys on Alpha spread the gay germ among Bravo in order to even things up, population-wise.

    Thoughts?

    • Abelard Lindsey says:

      ..if homosexuality is caused by a pathogen, wouldn’t it be possible to weaponize it?

      Eventually yes. Lots of infectious agents affect behavior. The biochemical mechanisms are currently poorly understood in many of these cases. But that will change as biotechnology advances (think Carlson’s Curves).

    • gcochran says:

      Sure, possible. I had a friend who constructed a Gay Pearl Harbor scenario.

      Hmmm… maybe I should call up DARPA?

      • Please don’t call up DARPA. The kind of people who will run things for the forseeable future would choose the worst possible targets (worst, that is, for civilizational purposes), cf., urban renewal and similar programs in the middle of the last century.

        That leads me to this conclusion: The attitude of that inspired fool from New Zealand that you mentioned may be a blessing in disguise. But for that intentional blindness, the Cool People would be the ones picking targets. I hope that your theory doesn’t gain currency until a somewhat sane regime takes power and treats this thing like polio.

        I can dream…

  5. J says:

    Your hypothesis would explain why victims of homosexual child molestation frequently mature to become homosexuals themselves.

    Do you think that homosexuality in other animals (i.e., giraffes and sheep) is likely caused by such a pathogen?

    I am not an expert in genetics, but I have hypothesized from my armchair that homosexuality is the “rock star gene” gone awry, akin to how autism could be the “nerdiness” gene gone awry (during prenatal development or whathaveyou). Wikipedia says the MZ twin concordance for autism has been found to between 36% and 95%, depending on the study and how narrowly “autism” is defined. Perhaps the problem with the seemingly low heritability of homosexuality is how homosexuality is defined – is the sexual preference the most fundamental aspect or is it a chance emergent property of a multitude of other inherited traits? We know that there are many ways to stereotypically “act gay”, so homosexuality is not merely a sexual preference, it’s a whole suite of behavioral traits. Flamboyance and high levels of feminity/artsiness are seen at very high rates in extremely promiscuous and sexually desirable male rock stars/preformers, who presumably act to spread their feminine traits in the population. Perhaps the non-gay MZ twins in the homosexuality studies you cite are abnormally effeminate or flamboyant or secretly bisexual, but by some chance developmental factor didn’t end up as strongly “gay” as their twin. (Also, there may be significant social pressure to lie about such a thing which would skew results)

    • JayMan says:

      Flamboyance and high levels of feminity/artsiness are seen at very high rates in extremely promiscuous and sexually desirable male rock stars/preformers, who presumably act to spread their feminine traits in the population.

      That’s part of the sib selection hypothesis of Zietsch et al., who found that heterosexuals with some opposite sex traits do have more sex partners than those who don’t, and the heterosexual twins of homosexuals also have more sexual partners. Autism was an excellent analogy.

    • gcochran says:

      Homosexuality is unusually common in sheep. Defined as a ram who is always totally uninterested in a ewe in heat tied to a fence in front of him. It is likely caused by some pathogen.

      Try to imagine what the equivalent of a rock star was in most of the human past: in a peasant society like Medieval Europe (or Sumeria) ; in hunter-gatherers. Nothing similar existed.

      • J says:

        Perhaps there was not such an elevated societal platform for flamboyant men in the past, but could not those who exhibited “rock star” traits still have had a culturally subterranean reproductive edge in the past?

        For example, the arts always seem to have been a haven for gays and sexually ambiguous men, and it seems to be human nature for artists to attract groupies. Certainly in modern times male poets and artists of all kinds frequently exhibit effiminate or flamboyant behavior. Reknowned pick-up artist Mystery is decidedly effeminate in mannerisms and presentation, not unlike a Mick Jagger or David Bowie. The overly flowery language of medieval Cassanova types perhaps stems from the same genetic suite of behavioral traits. Also, preachers and politicians share many similar characteristics with rock stars – they have to sway large audiences with pretty words, and keep attention drawn on themselves. Indeed, the high ratio of homosexual to heterosexual sex scandals of Churches and politicians worldwide could be interpreted as circumstantial evidence that both gays and gayish heterosexual men tend to channel their reproductive energies in roles where they use their natural flamboyance and artsiness to attract mates.

        Also, while flamboyant, artsy, effeminate men certainly have a larger cultural presence now than ever before, could that very trend explain the increased frequency of homosexuality in our culture vs. medieval/hunter gatherer times?
        It would take civilization reaching a certain level of prosperity for effeminate men to gain a reproductive edge by being weak yet flamboyant artists and seducers – how many men can earn a living in the arts, in Malthusian conditions? And as Western Civ emerged from this malthusian backdrop, perhaps that new freedom allowed heterodox reporductive strategies like male flamboyancy to flourish. In a pond full of big fish, brightly colored guppies certainly won’t flourish, but once in an aquarium, they do.

      • JayMan says:

        @J:

        I agree with you that men with “rock-star” like personalities would have had a great edge in earlier times, especially among the upper classes of Medieval Europe. These were the Cassanovas, Rasputins and Klemens von Metternich’s of the time—the Mic Jaggers and Hugh Hefner’s of their day. Having a way with the ladies is always good for a man. If a touch of “feminine” flamboyance greatly boosted a man’s mating success, it would surely be worth losing a few potential nieces and nephews that the occasional gay brother failed to sire. Well, for some men, anyway; obviously being a playboy wasn’t something all men could do, particularly in a society where most people were confined to backbreaking farm work that required strict monogamy. But among the upper classes, where the peasants do the work for you (and fight the wars for you), all was fair game. The flamboyant playboy is likely an evolutionarily stable strategy in settled farming societies without a history of violent struggle for mates and with a solid class of elites. Gay men are an extreme form of this trait just like autistics are perhaps extreme nerds.

  6. j says:

    can you explain what you mean by ‘syndromic versions’?

    • gcochran says:

      Consider deafness. At this point, most congenital deafness is caused by genetic factors – mutations in many different genes that are involved in hearing. Some of those mutations, about 15%, have other effects as well. The best-known example is probably
      Waardenburg syndrome, where deafness is accompanied by a white forelock.

  7. JayMan says:

    A couple of thoughts:

    1. The absence of homosexuality from hunter gatherer societies (presumably the Bushmen) might indicate that the trait did not appear in that group, but perhaps it appeared in more recent lineages.

    2. The existence and prevalence of homophobia indicates that whatever the source of homosexuality or its purpose, evolution seems to have crafted a defensive response, which apparently has something to do with protecting the sexuality of children. Homophobia also seems to appear to exist among individuals to protect themselves from their own homosexual leanings (ala Ted Haggard, Marcus Bachmann, possibly Rick Santorum). However, this is not necessarily incompatible with the view that a pathogen is to blame. If Gallup is correct, and the fear that pubescent boys might be molested by homosexual men is the motive behind homophobia, then it’s possible that such abuse might serve to spread the pathogen from the abuser to the victim (if it’s an STD)—which is a better explanation than sexual “imprinting”.

    3. Why is homosexuality unlikely to have a kin-selected advantage? If kin fecundity is boosted by genes for homosexuality, would that not offset the loss of fertility to the homosexual individual?

    4. The prevalence of homosexuality seems to vary by place and time. It seems fairly safe to say that homosexuality was much more common in ancient Greece and Rome and seems to have even been tolerated. I’ve suspected that the reason that homosexuality declined after that era was because of this tolerance; if enough men didn’t marry or produce children because of same-sex relationships, the genes for the trait would have diminished. That and the influx of genes brought by the German invaders may have reduced the trait to somewhere near its present levels. In this case, if a pathogen was to blame, genetic susceptibility must be in play at some level, because otherwise this requires that the disease load had to crash as Rome declined.

  8. Jim says:

    I recall reading a long time ago some writing by an anthropologist where he stated that he had a hard time even explaining homosexuality to Eskimos. When they finally understood they burst out laughing. He said that they were either wonderful actors or they had never heard of such a thing.
    However I have also read that many of the shamens among primitive people are homosexuals.

  9. MikeP says:

    The viral hypothesis would make better sense if there were a clear selective advantage for the pathogen to change the behavior of the host. In this case there’s no obvious advantage for the pathogen and there remains a strong selective disadvantage for the host. If viral induced, one would still expect strong selective pressure for resistance and low incidence of the “disease”.

    Was it E. O. Wilson who first proposed selective pressure at the group level to explain the high incidence of homosexuality in men? Regardless, the fact that homosexuality is much more common in men than women suggests that selection at the group level still remains a viable hypothesis. Groups can’t spare women, but they can spare men. Having a few men stay with the women is advantageous for several obvious reasons, including helping with child rearing, protection from predators and other humans, and a society with less male-male conflict. Gay men do tend to get along very, very well with women and women the same with gay men (just watch last night’s episode of “Survivor” for a perfect illustration – sorry). Also, the capabilities of gay men do seem to be particularly high. They combine the higher intelligence of men with the skills and interests of women – a combination that seems highly useful to our species at the group level. As human society arose and developed, perhaps gay-adapted groups were able to conquer gay-free populations. The distribution of homosexuality that you note, viz. the absence of homosexuality in hunter-getherers and high incidence in modern societies, doesn’t suggest a virus at all, but rather the replacement of small gay-free groups by larger gay-adapted groups of humans.

    • JayMan says:

      Female homosexuality may be comparatively rare, but female bisexuality may be very common—as high as 15-20% in some studies.

      • ziel says:

        GSS results on sexuality are fairly consistent year-after-year. If you look at the SEXSEX5 variable for ages 18-25, you’ll find about 2% homosexual and <1% bisexual for males. Young females definitely have higher bisexuality incidence than exclusively homosexual – usually <3% homo and 3-5% bi. The 15-20% incidence doesn't seem plausible (perhaps for teen girls they're including playful behavior in these other studies).

        Interestingly, non-hetero behavior seems to decrease for females with age while increasing for males.

      • JayMan says:

        @Ziel

        The evolutionary purpose of female bisexuality may be to attract men. There was a nice little hypothesis on a link that seems to have died, so I’ll recap: it goes that in polygynous societies, men have an incentive to mate with lesbians since they are less likely to have had sex with other men (hence increasing the likelihood that her offspring would be his). Female bisexuality then evolved as a mimicry strategy to illicit the same reaction in the alpha man without giving up mating with betas. As such it would follow that female same-sex behavior would decrease as they age as these women presumably have settled down with men. I will say anecdotally that almost all the bisexual women I know are primarily hetero and all seek to settle down with men.

        Perhaps variation in how the question is asked leads to variation in the result, but several studies do report a ~15% figure for non-hetero orientation among young women.

    • gcochran says:

      Group selection is impossible. Look, here’s what it would take. You’d have to have lots of little tribal groups in contention, constantly wiping each other out, and with the winner picking up almost zero genes from the loser – and homosexuality would have to help the winner win. The first part of the scenario might have some truth to it in prehistory, the second part almost certainly does not.

      Moreover, nobody knows of any concrete evidence for any kind of fitness payoff to homosexuality at either the individual or group level. You could just as well make a case for group selection causing high levels of blindness or liver failure.

      • TWS says:

        My evidence is entirely anecdotal and from observation but homosexuality is fairly common in Native American communities (I’ve lived and worked on rez’s all my life). Speaking to some elders in private, some groups have reported an acceptance of what we would call pedophilia and homosexuality in the pre-European dominated past. Some communities have tons of pedophilia and some do not. The communities that have the tons of pedophilia also seem to have lots of homosexuality or ‘intox-sexuality’ (the first person to pass-out, male or female gets to be the ‘girl’ for the night).

        I know they are not technically ‘hunter gatherers’ but there are those tribes in New Guinea that practice homosexual pedophilia and believe that ingestion of semen is necessary to ‘make a man out of a boy’.

        If our more dimorphic and robust ancestors were more polygamist perhaps homosexuality (man/boy) was an outlet for sexual urges for those men that could not compete with the alpha types?

    • gmariamen@comcast.net says:

      “Also, the capabilities of gay men do seem to be particularly high. They combine the higher intelligence of men with the skills and interests of women …”

      This is an oft-repeated meme that, as far as I know, has never been substantiated by any study. Even anecdotal evidence suggests otherwise: I have taught thousands of teens over three decades, and while it’s true there’s no way for me to know if numerous Bobs who didn’t appear to be gay were or weren’t, I am fairly sure that the Bills who appeared to be gay, in all likelihood, were. Further, I can tell you that the smarts of Bills ranged from dull to bright. The creative capacities ranged from non-existent to impressive.

      I think celebrity has led us to conclude that gays are talented or smart because they are OUT there, hard not to notice even when they were in the closet. Then, there’s the simple notion that people gravitate toward fields where they feel less threatened. It’s always been a fact that the different aren’t judged as much in the arts as in other fields, no matter the nature of their difference. In fact, much of what we call the artistic fields welcome the odd and the atypical, even if no real talent is demonstrated. Recall the actors who traveled from town to town–outcasts, for all kinds of reasons. Then too, kids who perceive themselves as different often seek solitary pursuits.

      Cochran wrote that gay men don’t populate the hard sciences much. (I don’t think he was joking, but then, it IS GC.) Is that a reflection of lack of smarts? Or a reflection of a social nature that can’t be accommodated in such fields? Or the closet? I don’t know.

      • gcochran says:

        I would guess that the IQ distribution in gay men is the same as the general population from which they are drawn. If it were lower, you wouldn’t see lots of talented writers and such.

        As for their cultural prominence, it occurs to me that there are jobs that have low median pay but give a few people lots of money and fame, acting for example. Someone with a family to support might not be able to take that kind of chance. On the other hand, professional sports is like that, and gay men aren’t common in sports.

        Gay men in the hard sciences: i think it’s different interests, not lack of smarts.

        • chozang says:

          “As for their cultural prominence, it occurs to me that there are jobs that have low median pay but give a few people lots of money and fame, acting for example. Someone with a family to support might not be able to take that kind of chance.” This thought occurred to me a long time ago. In addition, there’s often a long period of time where actors must “pay their dues”, and men with families (or pursuing families) are not as interested in living poorly for an extended period of time.

          On the other hand, any profession that requires a doctorate has the same kind of delayed earnings, but maybe this is offset by a more realistic chance of payoff in the future.

      • The Man Who Was . . . says:

        In sports, it is usually pretty easy to tell who is going to make it or not at a fairly early age, by the early 20s at least for most sports. There are a few late bloomers in a few sports and positions, like quarterback in football, golf, maybe some others, but its not like the arts where its not at all unusual for your career to take off in your 30s or even later.

    • Traherne says:

      I don’t see why there necessarily has to be a selective advantage for the pathogen. What selection advantage is their for a pathogen that causes its host to nod off now and again, as in the case of narcolepsy?

      • gcochran says:

        Well, it might be molecular mimicry. Sometimes a pathogen can hide from the immune system using surface proteins that look like the host. Sometimes the host immune system misfires and strikes that part of the body with those proteins… this happens with rheumatic fever, where the immune system can attack the heart, and, sometimes the brain (Sydenham’s chorea). The similarity of the strep surface proteins to those of the host is not a coincidence. It is a product of selection. But the long-term damage to the heart valves does not really benefit the pathogen. It’s a side effect of an adaptive strategy.

      • Traherne says:

        MikeP–Or for that matter, is there a reproductive advantage for rubella in making its host deaf?

    • gcochran says:

      E. O Wilson is innumerate.

      • MikeP says:

        Different, but related: Wilson, with a couple of mathematicians, is now trying to debunk the theory that kin selection has been the pathway to eusociality in the Hymenoptera (evolved multiple times in the order). Kin selection and haplodiploid sex determination has been broadly accepted by hymenopterists as the explanation for the repeated evolution of eusociality in Hymenoptera (fwiw, I’m a hymenopterist). I don’t know if he would now similarly reject the idea that kin/group selection has played a part in the prevalence of male homosexuality in humans.

  10. jb says:

    Until recently, didn’t most homosexual men still marry and have children, simply because that is what was expected of men in pretty much all cultures up until now? And wouldn’t that relax any selective pressures against homosexuality? It seems to me that this would open up a window for theories which might be untenable under the assumption that homosexuality has always had a drastic reproductive cost.

    One thing that disinclines me to believe in a genetic explanation for homosexuality is that there are so many other types of abnormal sexuality that need to be explained. So is there a genetic explanation for pedophilia? For sadomasochism? For foot fetishism? It’s a very long list, and everyone seems to overlook it when talking about this issue, which I think is a mistake. It just doesn’t seem plausible to me that all aberrant sexuality can be explained genetically. And once you accept that human sexuality is flexible, and that, for example, coprophilics aren’t “born that way,” do you really need a separate, genetic explanation for homosexuality?

    • JayMan says:

      Until recently, didn’t most homosexual men still marry and have children, simply because that is what was expected of men in pretty much all cultures up until now? And wouldn’t that relax any selective pressures against homosexuality?

      Quite likely yes.

      One thing that disinclines me to believe in a genetic explanation for homosexuality is that there are so many other types of abnormal sexuality that need to be explained. So is there a genetic explanation for pedophilia? For sadomasochism? For foot fetishism?

      Why not? As Robert Trivers noted, 50% of the human genome expresses itself primarily or exclusively in the brain. That’s a lot of potential for variation.

      Even if a pathogen is involved in causing homosexuality, which I believe is very possible, genetic factors are still involved because susceptibility to the pathogen would have to vary.

      • Anonymous says:

        “Until recently, didn’t most homosexual men still marry and have children, simply because that is what was expected of men in pretty much all cultures up until now? And wouldn’t that relax any selective pressures against homosexuality?”

        “Quite likely yes.”

        Quite probably not.

        Paleolithic humans were more sexually dimorphic than modern humans, which is evidence that they were largely polygamists who engaged in (presumably) brutal competition for mates, with females being transferred frequently from one dominant male to another man as circumstances changed. Uncontacted hunter gatherer groups found today often show this pattern. They didn’t “expect” one man-one woman monogamy, like some Stone Age version of Pat Robertson or Jerry Falwell, in the least bit.

        Homosexual men, who don’t desire sex with females at all, would have no reason or drive to participate in this competition, and other males would have certainly no incentive at all to force them into competing.

      • JayMan says:

        @Anonymous:

        Paleolithic humans were more sexually dimorphic than modern humans, which is evidence that they were largely polygamists who engaged in (presumably) brutal competition for mates, with females being transferred frequently from one dominant male to another man as circumstances changed.

        No doubt polygyny is the rule in foraging societies. And indeed, homosexuality could confer no adaptive benefit in such a society. And of course, it doesn’t seem to exist in such societies. I would imagine that any adaptive benefit of same-sex orientation (or whatever benefit it confers to kin) would work best in a settled farming society with less male-on-male violent competition and possibly primarily monogamous.

    • gcochran says:

      Imagine a mutual fund that invests all its money in lottery tickets. For every dollar they put in, they’ll get about 40 cents back. They keep doing this. Isn’t 40% better than nothing? Won’t that capital hang around forever? Get the hint?

    • erica says:

      “So is there a genetic explanation for pedophilia? For sadomasochism?”

      How about “intertwined circuits” to explain the connection between violence and lust? It’ll be interesting to see where further research take us in this regard.

      http://www.nature.com/news/2011/110209/full/news.2011.82.html

    • chozang says:

      “One thing that disinclines me to believe in a genetic explanation for homosexuality is that there are so many other types of abnormal sexuality that need to be explained. So is there a genetic explanation for pedophilia? ” I assume you’re referring to true pedophilia (the desire to have sex with actual children, those who are not yet capable of reproduction) rather than the popular usage of the term, which also includes those who desire to have sex with biological adults who have not yet reached legal age.

      There could be a value in establishing a sexual relationship with a child so that sex is still occurring when the child reaches puberty.

      Regarding the paraphilias you mentioned, as long as they do not replace intercourse, then they can be thought of as foreplay, rather than as a replacement for intercourse.

  11. j says:

    It is easy. Visualize a tiny AIDS like organism that, when injected into male babies, turns them into homosexual men. Those parasited men develope increased sexual appetite and maintain an exceptionally intense sexual life with many different men. The parasite is transmitted by sexual contact, probably by semen or blood. Turning a baby boy into a homosexual converts him into an active diffuser of the parasite.

    How is that some boys turn homosexuals and others- even identical twin brothers – do not? The boy who grows up to be a homosexual has been infected with the parasite at an early age. Since we are visualising a parasite transmitted by sexual contact, it can be assume that the babies who are to be future homosexuals have been in close contact with a homosexual who infected them. We may be talking about some kind of pedophilia.

    The people has instintive horror of pedophilia and it is severily punished. The instincts of the people generally are found to be justified. Now remains the problem of identifying the organism.

  12. Jim says:

    Cochran – Do you think that male and female homosexuality are both caused by the same infectious agents? Also are the behavioral changes in the host an accidental side effect or could they be advantageous to the virus (or whatever)? Male homosexuals have generally many more sexual partners than most male heterosexuals which might be advantageous to a sexually transmitted agent. Also the modes of intercourse among male homosexuals are more likely to result in transmission of an infectious agent.

  13. dave chamberlin says:

    Unless you can back up your assertion with defining the means of transmition of this pathogen with a study that confirms it all you are doing is pissing off a lot of people who think they know what they are talking about, but don’t. Now that wouldn’t be one of Greg Cochrans favorite pasttimes, would it?

    Again, thanks for another thought provoking thread. I too can’t imagine homosexuality being adaptive or mutational. But I would think if it was purely caused by pathogens epidemiological studies would have revealed that by now. Anyway I can’t help but think Cochran is having a lot of fun with these hot button topics. Briefly reviewing the scientific literature I read that each older brother increases the odds of a man being gay by 33%. This is a considerably higher correlation than the previously mentioned 25% likelyhood that a man is gay if his identicle twin is. Any thoughts?

    • Tschafer says:

      I have no idea if homosexuality is caused by a pathogen or not, but any theory that causes the politically correct this much anguish has at least some value…

    • gcochran says:

      I’m dead serious. it has to have a cause, and a pathogen is the most likely cause. Realize that the number of people who are actually trying to find out the cause of male homosexuality could be counted on the fingers of Frodo’s right hand. Nobody wants to know. Except for me, of course. I know of two people who independently came up with a similar notion: one suggested that we never tell anyone, the other didn’t want people to know that he had ever thought this. But then, he was at Harvard.

      • dave chamberlin says:

        I appreciate the response. I don’t doubt you for a second that research in this area is the kiss of death for a researchers career.

      • erica says:

        What research there is still seems to be concentrating on finding genes: Sanders at Northwestern, large sample GWAS of gay brothers, funded by NIH, results almost two years overdue…(ahem, wonder if they are having a hard time finding anything they can hang all the initial publicity on?) When the study began, Sanders got a lot of air time, smiled a lot, along with news anchors who crooned that not IF, but WHEN gay genes were finally identified, as they surely would be in this study, all “homophobia” would have to disappear. (Actually, I like your word “homoaversion” better.)

        Sanders is a “psychiatric geneticist.” I really don’t know what that is. I can only guess he’s a guy looking for genes for behavior. He has said he believes a complex combo of genes and nurture likely are the cause, which strikes me as a statement that tries to cover all bets.

        Dr. Cochran, Bailey is on Sanders’ team, as I have read, and over at Sailer’s blog, I believe it was, you mentioned you had recently spoken to him. I would imagine he gave you some insight into what it was they are seeing or not seeing in those DNA samples. Nada?

        In order to please a certain political group or two, and in order to get more monies with which to either study or play with money, I’d guess there’s a lot of pressure to find something, anything!

        I know Roselli, the sheep expert, is still looking for fetal hormonal explanations, but even then, it’s just as likely a germ has affected the pregnancy and the development of the fetal ram…if it’s the fetal ram, not the newborn or young ram that is so affected.

        • gcochran9 says:

          I think there are no results yet, but I am told that there probably will be some fairly soon. I sincerely doubt that they will find any particular locus that has much effect. That’s from my theoretical perspective, not because of any inside information.

    • I read that each older brother increases the odds of a man being gay by 33%.

      Maybe the placenta gets more permeable for the pathogen, the more births a woman had?

      From
      http://www.dailymail.co.uk/health/article-173878/Boys-big-brothers-likely-gay.html

      Second, third and subsequent unborn male babies in the womb are exposed to more testosterone – something which may go back to when younger siblings needed to be stronger to survive if food was scarce.

      There are also higher levels of antibodies in the womb for subsequent sons which could affect the orientation of the brain.

      But not all the experts believe Dr Blanchard’s theory because there is no evidence that Roman Catholics and Mormons, who tend to have large families, produce more gay men.

      Social scientists also point out that the theory would mean the trend for smaller families in the Western world would mean fewer gay men, too, and that doesn’t seem to be true either.

  14. Jim says:

    Of course promiscuity among male homosexuals really wouldn’t help the virus spread since the individuals having sex would both be homosexual and so already infected. In fact if the virus is sexually transmitted wouldn’t the best thing for the virus be sex with uninfected individuals? So if the virus causes changes in sexual behavior the most likely would seem to be an increase in normal sex drive directed towards normal partners who would be more likely to not yet be infected.

    • j says:

      Yes, sex with other infected persons would not advance the parasite, but with yet uninfected children – yes. Basically we must be talking about a pedophile parasite.

      • erica says:

        I’d guess side effect of a pathogen before a parasitic infection that manipulate behavior, but for the sake of argument, consider that exclusively homosexual men ( by that I mean men with no desire for women) do have sexual contact with straight men, both today and historically.

        Let’s say a gay man with such a parasite or a germ services a straight man through oral sex. Straight boys/men have such contacts in boarding schools, in military settings with no women available, in prisons, etc.

        Pathogen/parasite is transmitted to straight guy who transmits it to wife, girlfriend, who may transmit it to child. Only a young child or infant would be susceptible to the parasite or germ and not all infants would be affected in that way. After all, not all people exposed to a cold virus gets symptoms of a cold. Or the straight guy himself could transmit it to his own child with whom he is in constant close contact. That so many children who wind up gay were noticed as gender atypical even in early toddlerhood suggests that if it’s a germ or parasitic infection, it happened early in life.

        I see no reason to believe such transmission has to be through anal penetration since I’ve read that homosexual practices in many cultures and even in American culture of the past often did not involve anal sex but rather frottage and oral sex. There are those who say that the gay liberation of the 60s and 70s promoted anal sex and that previous to that other practices were more common.

      • erica says:

        “sex with other infected persons would not advance the parasite”

        You don’t need to jump to pedophilia. Most gay guys have not been contacted by a pedophile.

        To sum up what I said previously, if you’re looking for parasitic manipulation, consider that gay men are find most sexually appealing masculine men, men not likely to themselves be gay. Any successful encounter with a straight man might turn him into an intermediate host. If it’s not a parasite making a temporary stop, just a bug, that straight man could be a carrier.

  15. harpend says:

    How good are the data that being molested by a homosexual male in childhood increases the probability of a male being homosexual as an adult. I don’t believe it but am willing to learn….

    • Sean says:

      If a bug causes homosexuality but does not spread by homosexuality there is no selection for the bug evolving to continue to defeat the immune system of humans and make them homosexual. But the human’s immune system has the very greatest of incentives to stop the bug. Those populations who were early adopters of civilization and urbanized living, where the bug could spread easily, would be selected for defences against infection, by whatever vector, with the bug. That wouldn’t stop the spread of the bug, but the bug would be faced with ever increasing human immune defences in that particular population as long as it caused homosexuality. Wouldn’t the outcomes be:-
      [1]. That the longest civilized populations became the most resistant to infection with the homosexuality bug . (Is that in fact the case ?). .
      [2] That the bug evolved away from causing homosexuality and towards a strategy of maximizing its spead by nonhomosexual vectors.

      —————
      (Separate point): I suppose it must be true about homosexuality being very rare among Bushmen, but Amerindian populations (including hunter gatherers) seem to always have had a significantly higher rate of homosexuality than other populations, and still do I think.

      • Traherne says:

        As noted above, there’s no reason for the pathogen to benefit directly. It can merely be a side effect of an adaptive strategy, as in the case of narcolepsy.

      • sean says:

        Narcolepsy has a prevailence of only 0.026% and it’s an excess of an adaptive function rather than its elimination. With sexuality the analogy is being intensely sexually aroused every hour for no reason. Why is there (virtually) no condition where the sleep mechanisim is knocked out by a bug and they never sleep – because that has been selected against very strongly since never sleeping will lead to death. If homosexuality is a side effect why would forms of the bug which do not cause homosexuality not have become more common than other ones.

        A specific bug that causes most cases of homosexuality has to spread by homosexuality Or it is a bug that virtually everyone has got, and it only damages a few (“%) it infects. But if universal infection is the case there would be quite a bit of selection against being damaged by it and homosexuality would not be at the 2% level of prevalence.

        If it exists it is a bug of homosexuals, and spread by them though homosexuality.

      • erica says:

        @Sean
        “Narcolepsy has a prevailence of only 0.026% and it’s an excess of an adaptive function rather than its elimination.”

        1.) The last I read, the hypocretin, missing in the sufferers of narcoleptics, enables people to react to sunlight and wake up. I don’t understand what you mean by its being absent as “an excess of an adaptive function” . Okay, I guess you mean sleep is adaptive. Necessary, yes, to conserve energy and to revitalize, but were we once sleepless?

        2.) “A specific bug that causes most cases of homosexuality has to spread by homosexuality Or it is a bug that virtually everyone has got, and it only damages a few (“%) it infects. But if universal infection is the case there would be quite a bit of selection against being damaged by it and homosexuality would not be at the 2% level of prevalence.”

        Lots of viruses infect almost everyone yet seem to do no visible damage to most, Think of measles making some males sterile. Think of a strep infection leaving some kids with strange neurological symptoms (see PANDAS). Some common respiratory viruses may be responsible for life-long asthma in some. Why is it hard to think that a bug which “virtually everyone has got” can have side effects in just a few percent.? Think of this too: it’s possible, isn’t it, that many us have been living with “side effects” to common infections, yet aren’t even aware of those side effects? They may be doing slow damage in any number of ways we’ve yet to discover. Homosexuality is simply noticeable at some stage.

        As for selection…the human body can evolve to fight off bugs, and the bugs can just go right on evolving and finding ways to infect us. Cockroaches evolve defenses against pesticides quickly….just think what a virus can do.

      • Sean says:

        The selection I was thinking of would be between strains within that species of bug, why would a bug cause homosexuality so often if it didn’t have to., (ie in order to spread). A bug that could infect without causing homosexuality would do so, Even if it was universal 2% of cases is a lot for a side effect . If the a bug doesn’t spread by homosexuality it would evolve away from doing so, just as in a society where nonconsensual homosexuality (like in Melanesia) was common, it would evolve towards speading by homosexuality . Assuming universal infection 2% is still a huge proportion suffering serious damage.

        “Lots of viruses infect almost everyone yet seem to do no visible damage to most,” The immune systems that suffer damage (are in a homosexual) get largely removed every generation. A virus can easily evolve to beat immune systems and continue to cause homosexuality in those it infects. But, would it if it didn’t need to?

        If a bug didn’t spread by homosexuality there would be no selection pressure to keep its rapidly evolving forms causing homosexuality . A single-bug cause is unlikely IMO.

      • Sean says:

        ‘If a bug doesn’t spread by homosexuality it would evolve away from causing it ‘ is what I meant to say. I am assuming that being homosexual does not make one spread infection by some none sexual form of contact. (For example if something about being homosexual resulted in standing too close and spraying spittle when talking or not washing hands with soap after using the bathroom.) Then, causing homosexuality would make perfect sense for a bug . But lots o’ bugs would be doing it in that case !

      • Sean says:

        Traherne, a side effects that appears in 2-100% of those infected ? It’s orders of magnitude too common. Narcolepsy isn’t.

      • erica says:

        @Sean,
        “Traherne, a side effects that appears in 2-100% of those infected ? It’s orders of magnitude too common. Narcolepsy isn’t.”

        Okay, since Cochran often mentions it, try the prevalence of polio and its side effects:
        -from Wiki
        _______________________________________________________
        Outcomes of poliovirus infection
        Outcome Proportion of cases[4]
        Asymptomatic 90–95%
        Minor illness 4–8%
        Nonparalytic aseptic
        meningitis 1–2%
        Paralytic poliomyelitis 0.1–0.5%
        — Spinal polio 79% of paralytic cases
        — Bulbospinal polio 19% of paralytic cases
        — Bulbar polio 2% of paralytic cases

        Or what about polycystic ovary disease, affected as many as 10% of women, the numbers who are made “subfertile” very high, the numbers made infertile difficult to estimate?

        I believe narco is used as an example by Cochran to show that a very small population of brain cells knocked out causes huge changes in one important behavior while not changing much of anything else.

        BTW, latest research points to upper tract respiratory infections, such as those contracted with flu (H1N1) as triggering episodes of narcolepsy.

        http://www.medscape.com/viewarticle/748619
        http://www.infectioncontroltoday.com/news/2011/08/study-draws-connection-between-narcolepsy-and-influenza.aspx

      • Sean says:

        Erica, you’re missing my point (understandable, as it’s a constantly moving target). A specific bug result in a range of effects (as in the case of polio.) Polio spreads by fecal matter so it doesn’t care. So if a bug causes homosexuality, but does not spread BY HOMOSEXUALITY why does it cause a tight range of effects. Why is there not a range of effects from the putative bug on sexual behaviour. Why would a bug not leave a sizable % of men totally uninterested in sex. But actually homosexualty is vastly more common than asexuality. “Men deficient in the enjoyment of pleasures scarcely occur” (Aristotle) I think that’s because, although a bug can evolve to interfere with vitally necessary drives in a very specific and precise way, it can only do so if that interference helped it spread. Otherwise it would be replaced with bugs of the same strain that were damaging but not causing homosexuality specifically.

        “I believe narco is used as an example by Cochran to show that a very small population of brain cells knocked out causes huge changes in one important behavior while not changing much of anything else” But does that kind of specific effect, and largely only that happen in 2% – 100% of those infected for any bug. If it did what would that mean? I think it would mean a connection between the specific behavior change and the way the bug spreads itsself.

  16. Rachelle says:

    You may very well be right that a pathogen is involved in this. Possibly other factors are as well. I don’t suppose there is only one way to push a boulder off a cliff.

    While homosexuality itself may not be adaptive, I am not certain that it could not be a byproduct of something that is adaptive. Thalassemia might provide a parallel example of that.

    I have wondered before at what seems like a relatively high incidence of homosexuality among very talented people. Leonardo and Michelangelo and possibly Cellini come to mind, along with Wilde,Turing and probably Newton, to name a few quick examples. Is it possible that a genetic mix that usually is intellectually advantageous in civilization spins off homosexuality as a byproduct at a fairly steady rate? I don’t know, but it might be too soon to rule it out as one of several other factors, including pathogens. I wonder if the rate of male homosexuality is lower among primitive people than it is with those who have had a few centuries of civilization to brew in?

    With you, I truly doubt that homosexual molestation of a child increases the chances of adult homosexuality…but I also agree that unanswered questions are unanswered. I’ll change my mind if data warrants it.

    • Traherne says:

      Not likely. If homosexuality is a disease that’s a defense against another disease, that disease must be truly horrific.

  17. Paavo says:

    I thought that the immune response by mother against the fetus was the fashionable theory. What’s wrong with it?

    • gcochran says:

      You’d expect natural selection to make that rare. Mammals have had something like 200 million years to get this right.

      • Paavo says:

        Maybe they get it right enough, but there are miscarriages and Rh-disease. I vaguely remember an old physiology lecture (might have been a dream) that a lot of children suffer from some mild Rh-disease type of attack by mother’s immune response, and that might be part of the explanation why younger siblings are smaller and have more health problems. Isn’t this the story to fit the younger brothers are gayer-observation?

      • TGGP says:

        I recall Greg having a post on GNXP about the unusually large rate at which human pregnancies result in a miscarriage. I can’t find it now though.

      • e says:

        My great-great grandmother lost 7 of 13 children to rh incompatibility. My grandmother lost several as well. We have a long way to go before we get that right.

    • dave chamberlin says:

      The immune response by mother against the fetus is the best explanation to date for the largest factor found so far in increasing the chance of being homosexual. And that is you are 33% more likely to be homosexual for every older brother you have. But that doesn’t answer Cochran’s point, you would think natural selection would make that rare.

  18. Jim says:

    I have read Cellini’s autobiography and although he does mention once an incident of cross-dressing by an artist friend his own sexual affairs described in the book are all heterosexual
    unless I’ve forgotten something. I don’t think he was a homosexual.

  19. Steve Sailer says:

    What about Bill Welmer’s chimera theory? Any comments?

    • gcochran9 says:

      I think it’s silly.

      • Nanonymous says:

        Why do you think it is silly?

        Is homosexuality indeed virtually unknown among hunter-gatherers? Weber cites Koniagas of Kodiak Island and the Aleuts to the contrary, references to North American Indians homosexuality are quite common, and I thought that homosexuality was known among some Australian Aborigines? Is there any systematic study/review on this subject?

        • gcochran9 says:

          A couple of reasons. I look at the odds. Think of syndromes that are Darwinian diseases: that is, they substantially dinged fitness in typical past environments. Now consider the common ones, that affect more than 1 in 100 of the population. The great majority of such syndromes have been shown to be caused by some microorganism. Suppose we have a syndrome of that sort that is not yet explained, like homosexuality. The default explanation is that it too is caused by some microorganism. Since no diseases has ever been definitely shown to be caused by microchimerism, it ranks really low on my list. Moreover, imagine that microchimerism did cause a problem: selection would tend to reduce it over time, and there would be no countervailing tendency, since the foreign cells (as far as we know) do not propagate further and hence do not evolve.

        • chozang says:

          Bisexuality appears to be common among the Pirahã. Though if it doesn’t interfere with heterosexuality, then it might be a different question.

  20. rachelley2003@yahoo.com says:

    Jim, I too have read Cellini’s autobiography…almost everyone has…and he does not mention homosexual experiences in it, but then he wouldn’t. It was a humiliating crime and not something to boast of in a personal account. I mentioned Cellini as possibly being homosexual because I recall reading that he was convicted of sodomy.

    In any event, it still strikes me as odd that so many highly talented people have been homosexual…or so it seems. Perhaps it is a misperception on my part.

  21. W says:

    I used to put a lot of stock in the gay pathogen hypothesis because I’m gay and when I was in my teens and twenties I was extremely sexually compulsive. It really was like something else would just take control of me and I would go out to parks/adult movie theaters or online cruising for sex. I honestly couldn’t stop myself, despite having some very good reasons (one of which is spelled A-I-D-S) to do so. But if some parasite was affecting my behavior, wasn’t I just spreading it to other people infected with the same parasite? What was the point of that?

    Although, as I understand the hypothesis now, it is that some common pathogen affects the brain’s development in a way that results in a homosexual orientation–maybe in just an insufficient masculinization of the fetus’s brain in the womb? That would allow for other causes as well. The mother’s immune response to the fetus, hormone levels in the womb, etc…. could all derail the masculinization process as well.

    One nitpicky thing about the comparison to narcolepsy is that it seems that people with it are just like normal people aside from their narcolepsy. But homosexual men aren’t just straight men who are sexually attracted to other men. Their interests and cognitive strengths are much more feminine.

    • rachelley2003@yahoo.com says:

      Is it the case that homosexual men necessarily tend to be more feminine than heterosexual men?

      That seems roughly true of many of them, but those who are are more likely to be noticed. On the other hand I recall a special unit of homosexual Greek hoplits, the Sacred Band, who were renowned warriors and who had vowed to fight together to the death. Were they effeminate? If memory serves, Alexander [with his father] killed all of them at the battle of Chaeronea, but then Alexander may have been homosexual to a degree as well. Homosexual men are attracted to men, beyond that I am not sure that they are necessarily more effeminate…but may be.

      In any event, I am still inclined to think that any one [or combination] of multiple factors, including pathogens or genetics, may result in homosexuality.

      • W says:

        Rachelle,

        I have known hundreds of gay men. Some I could see fighting as part of a Sacred Band, certainly. On average, though, gay men *do* tend to be more feminine than heterosexual men.

      • chozang says:

        It has occurred that male homosexuality accompanied by effeminacy may have a completely different cause than male homosexuality not accompanied by effeminacy.

    • wasn’t I just spreading it to other people infected with the same parasite? What was the point of that?

      Maybe the point was to infect bisexual men.

      One nitpicky thing about the comparison to narcolepsy is that it seems that people with it are just like normal people aside from their narcolepsy. But homosexual men aren’t just straight men who are sexually attracted to other men. Their interests and cognitive strengths are much more feminine.

      Maybe the pathogen starts a cascade, just like testosterone does.

  22. dearieme says:

    Somewhere I saw the remark that cancer was a thousand diseases with a common symptom. Homosexuality too?

    • gcochran says:

      I’d bet that most cases have the same cause.

      • Sean says:

        With one cause homosexuality would surely have been dramatically increasing or decreasing over the last century. Difficult to believe it has stayed at much the same prevalence. Autism certainly hasn’t.

        • chozang says:

          People take an autism diagnostic trend as an increase in autism. 90% of autistic people are mentally retarded. In the past, it just didn’t seem very important to most physicians as to whether a mentally retarded person was also autistic. I worked with mentally retarded people for several years, and I bet that if I had guessed before looking in their file as to which ones would have a dual diagnosis of autism, I would only have done a little better than chance.

          In general, psychiatric diagnoses are not made nearly as scientifically as people think. Two psychiatrists diagnosing the same person would probably often come up with different diagnoses.

      • lokkes says:

        Could be a family of causes. What do you think of endocrine disruptors, etc. as a factor in the modern rise of homosexuality? (BPA, etc.)

    • Rachelle says:

      “Somewhere I saw the remark that cancer was a thousand diseases with a common symptom. Homosexuality too?”

      Maybe…I think that was what I was wondering as well.

      I seem to recall that girls exposed to androgen-type substances in utero tended to have masculine interests and behaviors as adults but were not necessarily more likely to be attracted to other women. Possibly same-sex attraction is not the same thing as adopting characteristics of the opposite sex.

      Then there is the accidental experiment with the boy whose bungled circumcision led to his getting a sex change operation as an infant and being raised as a girl without being told that he was born male. [Read: ‘As Nature Made Him’ for an account]. Despite all the social structuring for him to be female his behavior marked him as being very different from the girls in his school. He [then she] was kicked out of the girls’ bathroom after trying to urinate standing up. Interesting how that was hardwired. When finally he was told he was born a male he immediately adopted a male role and lived that way, with a female wife or partner, until his suicide. On the whole, the idea of gender as a social construct did not fare very well in his case.

      It seems that we are complex enough for many things to wrong from genetic inheritance on through every stage of development. Not only does one wonder, “Why homosexuality?” but also “Why anything?” Why are some people incurably attracted to children? Why paraphilias? Why is anyone normal?

  23. Jim T says:

    Re homosexuality among sheep: cryptosporidium is common among gay men, and is the organism most commonly isolated in HIV positive patients presenting with diarrhea. Cryptosporidium usually inhabits the bowels of sheep.

    • erica says:

      That’s interesting, yet I’d imagine there are many pathogens common to sheep and humans (as well as other mammals). I know, for example, that a common respiratory infection of all children, respiratory syncytial virus, occurs in lambs as well. Lots of kids (humans) are hospitalized with RSV every year, and many die, but most kids are just miserable for time with it, and recover. And, it’s recurring, with no immunity from having had it.

      • Jim T says:

        I agree that there probably are many pathogens common among people and other mammals.

        This one though usually lives in the bowels of sheep and is common among gay males. In people it lives in the bowels as well and causes diarrhea, irritable bowel syndrome, etc.

  24. Rachelle says:

    Just a question. Would a pathogen also be responsible for female homosexuality?

    Are there other behavioral characteristics not related to homosexuality that might accompany the infection?

    I am not attempting to challenge the notion of a pathogen being involved in this. I am just wondering how else it might present itself if it is the cause.

    • Greying Wanderer says:

      “Would a pathogen also be responsible for female homosexuality?”

      It seems to me if it was a pathogen trying to transmit itself then in women it might display itself as promiscuity rather than homosexuality.

      Personally i wonder if there might be more than one cause – twinning-chimerism for those cases where a person seems like a jumble of male and female traits with more or less the same frequency for males and females and then a second thing which just effects males or effects females differently.

  25. j says:

    If such a complex mechanism could evolve like the cat-mice-parasite described in the note, one may imagine also some kind of Cryptosporidium-human-parasite mechanism. If so, we should look for some tiny organism parasiting Cryptosporium.

    • j says:

      Crypto’s life cycle is quite complex and is its transmission is by faeces. If we are talking about a parasite that rides on the shoulders of Crypto, then homosexuality exist only in areas where the population carries Crypto.

      It could be easy to overlay a map of frequency of homosexuality in human populations on a map of frequency of Crypto parasistosis. If it does not work, superposition of homosexuality frquency maps (I never saw one) with maps of other parasites (the WHO has them).

      On the other hand (I’m multihanded), why cure homosexuality? In the old barrio we had a saying: “Sarna con gusto no pica”. Let them enjoy it.

  26. Wait...what? says:

    Maybe the pathogen was actually introduced to humans by our ancient alien overlords. Makes just as much sense. *rolls eyes* This is not science… it is science fiction.

    • j says:

      “Sarna con gusto…” means scaies is not a (parasytic) disease for those who enjoy scratching. From Cervantes’s Don Quixote.

      • Kjersleif says:

        Hear, hear! Sarna con gusto no pica indeed.. Why does OP and others make such a big deal out of it? Why care? So what, some men like to fuck eachother..?

  27. johnmanor@hotmail.com says:

    The helpful gay uncle notion and group selection don’t seem to be supported by how gays actually live.

    The “gay lifestyle” just seems like a giant example of parasitic castration.

    • W says:

      Gay men may have been a lot more helpful in tribal societies, where there were no gay bars to spend their evenings in and gay cruises to spend their vacations on. I don’t realy buy it though either.

      • Dave says:

        Even if they were more “helpful”, I don’t think that would necessarily mean they weren’t parasitically castrated. They could be “helping” the parasite, whatever it might be.

        And what exactly would the gay men be doing that would be so unique and helpful that straight men couldn’t do or do similarly? Whatever it is, it is likely to be outcompeted by a straight male doing the same or similar while spending even just 30 seconds of his life having sex with and impregnating a female.

        • gcochran9 says:

          “it is likely to be outcompeted by a straight male doing the same or similar while spending even just 30 seconds of his life having sex with and impregnating a female.”

          Bingo.

      • j3morecharacters says:

        30 seconds? A man has to spend months courting and maneuvering a fertile female to get her to the point of carrying his baby. 30 seconds? Maybe in some Western hookup university dormitory, but then those are all sterile mutual masturbations.

  28. dearieme says:

    How about the “obesity epidemic”: could it be related to a pathogen e.g. one that suppresses the “I’m full up” response?

    • chozang says:

      Obesity has a possible survival advantage. This is probably the first time in history that most of the world was in an extended period of plenty. Throughout most of history, starvation was a bigger concern.

      Obesity is like having a bank account of calories. Unlike simply storing food in a shed, it cannot be easily stolen. There are drawbacks of course. It is a trade-off. So it is not surprising that there’s a range of weights that people have.

  29. Greying Wanderer says:

    “I used to put a lot of stock in the gay pathogen hypothesis because I’m gay and when I was in my teens and twenties I was extremely sexually compulsive….But if some parasite was affecting my behavior, wasn’t I just spreading it to other people infected with the same parasite? What was the point of that?”

    It just struck me – if there were human populations where heterosexual behavior is more or less the same as male homosexual behavior in the west then maybe it originally evolved in that population.

  30. j says:

    It’s not only homosexuality that may be caused by protozoa infection. Human cells raised in petri dishes, and infected with Toxoplasma, will respond to drugs like haloperidol; the growth of the parasite stops. Haloperidol is an antipsychotic, used to treat schizophrenia.

  31. Dave says:

    It just struck me – if there were human populations where heterosexual behavior is more or less the same as male homosexual behavior in the west then maybe it originally evolved in that population.

    There is some evidence that available ethnic demography better explain regional incidence of AIDS than the available HIV infection data: http://majorityrights.com/weblog/comments/the_mysterious_influence_on_the_us_of_the_human_immunodeficiency_virus

    The correlation between cumulative AIDS cases and HIV positive tests in 2001 is 95% but the correlation between cumulative AIDS and the conjunction of a largely black or hispanic population with a largely Jewish white population is 98%.

    These populations are known for promiscuous behavior and for promoting it, both for homosexual behavior in general and for heterosexual behavior that approaches the promiscuity of male homosexuals.

  32. Pingback: Perfidy - Science!

  33. Wait...what? says:

    “As for where this is going – I don’t believe it’d be hard to find out the cause, since we have a good experimental animal, sheep. 5-10% of male sheep in some herds are totally uninterested in females: you can tie a female in heat to the fence in front of them and they don’t do a thing. Males they hump. As far as I know, the only two mammals with a few-percent of males with this kind of preferential homosexual behavior are humans and sheep. The two species have often been seen together, and I doubt if this is entirely a coincidence. I’d bet money that the cause is the same, and that we contracted it from sheep. That’s thought to be the case for a lot of infectious agents – acquired from domesticated animals.
    Gee, so now we have to look for the gay sheep gene! Actually we already did: the condition doesn’t show noticeable heritability. They do show funny endocrinological patterns in the amygdala ( we get to dissect homosexual sheeo), but I’m sure you need to think more about neurotransmitters than they have so far. And about some infective agent, because of course that’s what it is.
    Well, though, one should be fair. Maybe sheep homosexuality is a variant genetic strategy – maybe the gay sheep show increased creativity. Maybe they help raise their nephews and nieces., even though no male sheep do zip for their kids, like most mammals.
    Maybe this sheep behavior was recently socially constructed! I could take this and run with it – but it would be wrong.
    As I said, probably not hard to solve, may even happen by accident, but almost completely unfundable. This is banned science: anyone who proved such a thing or even worked on it would likely never get any federal money ever again. Blanchard asked about HLA correlations – they wouldn’t release the info. This is something man was not meant to know. I have even had one biologist who secretly came to a similar conclusion (Alan Grafen, who wishes I wouldn’t mention his name) suggest if proven it should perhaps be kept secret forever. What a chickenshit.
    On the other hand a lot of the smarter evolutionary biologists think it has a pretty good chance of being correct. Bill Hamilton thought so. Trivers thinks it is much more likely than any other model he has heard of (of course he _is_ crazy) . Mike Bailey thinks it is the only evolutionarily plausible model that has ever been proposed.
    Posted by: gcochran at August 19, 2003 12:15 AM”

    Sooo… 9 years later, still speculating on the same old horseshit. Sorry, sheepshit.

    • gcochran9 says:

      Hamilton and Trivers thought that a pathogen explanation idea made sense: you don’t. Why?

      The cause is unresolved because nobody is looking.

    • erica says:

      “Sooo… 9 years later, still speculating on the same old horseshit. Sorry, sheepshit.”

      The “speculating” is called in its noun form a “hypothesis,” one which seems consistent with evolutionary tenets, that natural selection would not, could not sustain genes which lead to no desire to mate with women.

      You must believe another explanation(s) make MORE sense. Which one? I’d like your take on why another explanation makes more sense.

      Then, I’d like to know why you hold the pathogen hypothesis in such contempt. Why is that? Why should a person hold a hypothesis in contempt, esp. one based on sound principles, and one put forward by a respected theorist in the field of evolution?

      Why the emotionalism?

      .

    • z says:

      It’s OK if your brain can’t handle it, not everyone can be smart.

    • Maybe it’s transmitted by sheep cheese? Is there any statistic that links homosexuality to sheep farming?

  34. dearieme says:

    Why is it politically incorrect to assume that the cause is a pathogen?

    • MikeP says:

      The pc crowd sees this as passing judgement on homosexuality.

    • dave chamberlin says:

      I wondered the same thing. Considering homosexuality a mental disease would be damned insulting. Considering homosexuality curable is simply stupid. But considering homosexuality caused in part or all by genetics, pathogens, or a kwirk in human development doesn’t insult anyone. I know of people in the gay community that want to find a genetic cause for homosexuality, it will confirm that they are born that way. I don’t see how any real cause for homosexuality that is eventually discovered will insult anybody but then again I don’t think the truth hurts.

      • gcochran9 says:

        Of course it’s a mental disease: a Darwinian disease, which is the only reasonable definition of disease. Curable? Who knows? Preventable? Likely.

      • dave chamberlin says:

        What evidence do we have that homosexuality is a disease caused by pathogens?
        None that i am aware of
        What evidence do we have that homsexuality is a quirk in human development?
        Men are 33% more likely to be gay for each older brother they have.
        What does this prove?
        Nothing, yet, but weighing the existing evidence I can’t agree that it is most likely that homosexuality has a pathogen as its primary cause. Only 30% to 50% of human conceptions progress beyond the first trimester, isn’t our species unique in this? I wonder if this far higher spontaneous abortion rate than other species doesn’t hold clues as to why such a poor reproduction fitness feature such as homosexuality would be so common. Just my amateurish wondering, I defer to your greater expertise and am grateful that you even bother to personally explain yourself to a random internet crowd.

    • As soon as you find out the cause you can offer a cure or a prevention method.

      As soon as there is a cure, homosexuality will be fought against (by parents to be, just like now mongoloidism) and hence it’s eugenics and stigmatizes gays even more.

  35. Traherne says:

    I’m a big fan of the germ theory of homosex. It’s by far the only theory to make any sense. But I’ve always wondered one thing: might the “gay face” be an example of a syndromic homosexual phenotype?

    I find myself encountering certain homos, and I know it immediately simply because there’s something strange about their face. I realize facial asymmetries can themselves be evidence of a prenatal infection. (In fact, I seem to recall reading one study where schizo’s were accurately picked out from photos by on slight facial asymmetries.) But it still makes me wonder…

  36. j says:

    What would be the social consequences if the parasite theory was proved as right? A vaccine against homosexuality would follow in about ten years. In the meanwhile, homosexuals would be strictly isolated from children. That they dont want, I presume.

    AIDS was identified and “cured” in ten years. If society would recognize homosexuality as the horrible castrating disease it is, it could probably be solved in even less time.

    Maybe finding a cure for sheep homosexuality would be less problematic. Improving the profitability of animal husbandry – and it could be done under the radar.

    A Nobel Prize is waiting out there.

    • Abelard Lindsey says:

      Evidently, gays want to be gay.

      Who would have thunk it!

      Of course, this does fit perfectly with the theory that it is an infectious agent that influences behavior.

  37. Greying Wanderer says:

    “As far as I know, the only two mammals with a few-percent of males with this kind of preferential homosexual behavior are humans and sheep. The two species have often been seen together, and I doubt if this is entirely a coincidence. I’d bet money that the cause is the same, and that we contracted it from sheep. That’s thought to be the case for a lot of infectious agents – acquired from domesticated animals.”

    Which would fit hunter-gatherers not having it.

    • Greying Wanderer says:

      I guess it’ll be one of those things we’ll have to wait for the Chinese to research – maybe they are already?

  38. Ian says:

    Could the pathogen be a retrovirus? I’ve seen that explanation offered for schizophrenia.

  39. j says:

    May I advance a theory why society has done zero effort to find out if Greg Cochran’s theory is correct? All the while AIDS was identified and sovled in no time… I think that back in our fish brains we reproducing males are quite happy of the reduced competition. Why cure them?

  40. j says:

    J’s bottom line:

    Greg Cochran is an enemy of humanity by showing the way to end homosexuality! (I dont mean it literally!)

    Let them buggers fuck each other to oblivion so we have the girls for us!

    Society’s half-mindedness about drug abuse has the same darwinian purpose: Let them delirate in nirvana so we have even more girls for us!

  41. Joe Walker says:

    On the topic of homophobia, gay men tend to carry quite a few STD’s around with them. Now if gay men only engaged in homosexual activity then this would not be a problem but these men will often engage in heterosexual behavior and even marry which means that they can spread the STD’s to women who can then spread them to heterosexual men.

  42. erica says:

    While there may yet be no research specifically targeting a search for a pathogen, it would seem any research shedding light of the nature of sexual attraction and sex-specific behaviors would eventually lead to identifying, if not the immediate cause of homosexuality, then at least the molecular underpinnings of heterosexual attraction. Understand the molecular biology of that and wouldn’t it follow that we’d be more likely to see what went awry with the result of homosexuality? It might not be the most direct route, but it seems it will get us there and there are researchers in this area. Catherine Dulac of Harvard has made inroads to understanding the sexual behaviors of rodents, and has made surprising discoveries. When her team knocked out the vomeronasal organ of female mice, they got females with male behaviors, including male sexual behaviors. A couple of paragraphs:

    “From this data a model emerges that provides a novel hypothesis for the neural control of social and sexual behavior in the mouse. Our findings suggest that pheromone inputs act in wild-type females to repress male specific behaviors and to activate female specific behaviors. This implies that the female brain contains structures and circuits underlying both female (as well as male) specific social and sexual displays. This model raises the intriguing hypothesis that, similarly, pheromones in males could specifically inhibit the activity of female-specific centers, and activate male-specific nuclei. Our next goal: to test Trpc2-/- males to try to identify a possible female circuit hidden and repressed inside male mouse brains.

    “What about other animal species and humans? Can this model be used to explain what factors determine sex-specific behaviors in humans and other animal species? Human beings do not have a functional Trpc2 gene or vomeronasal organ and, unlike mice, they rely mainly on visual cues for social communication. Our model can perhaps offer a fresh perspective and experimental paradigm for the study of social behavior in humans and other species.”

    from http://mcb.harvard.edu/newsevents/news/Dulac6.html
    ***********************************************************************************************************************
    It looks like rodents have two circuits, one for attraction to males, another for attraction to females and the VMO and pheromone receptors control the sexual and other sex-typical behaviors.

    That last sentence indicates an earnest interest on the part of at least one researcher in providing a new “experimental paradigm” for human sexual behavior.

    Might humans have two circuits in their brain, one silenced in the typical male, one silenced in the typical female? Might the wrong circuit be tripped by a pathogen? The other overridden? Might one circuit not have developed due to a pathogen? Are there sensory inputs that are being misidentified by receptors?

    From an evolutionary standpoint, what is the likelihood that a rodent’s wiring for such a primitive instinct as attraction to the opposite sex is totally different from a human’s?

    I have no idea, but it’s interesting stuff.

  43. hbd chick says:

    @greg cochran – “Suppose there’s a neuron subpopulation that performs a key function in male sexual desire: wipe out that subpopulation, and Bob’s your uncle.”

    you mean: and bob’s your boyfriend. (~_^)

  44. patinoklahoma says:

    A question for Dr, Cochran. . .Any thoughts about stuttering? It affects about 1% of most populations (~80% are male). About half of stutters have a family history. (Mine does.) I participated in NIH study that looked for a genetic basis (Google “NEJM stuttering” for a link to article describing study), The study took DNA samples for American, British & Pakistani stutters and looked for mutations that were more common in stutters vs. normal speakers. The study found some interesting things in some of the Pakistani families that had very high frequency of stutters, but for the most part they did not find much in the US/Brit subjects. I go to a stuttering clinic in Virginia every year and Dr. Dennis Drayna from the NIH gives an update on research progress. Dr. Drayna said that when they started this effort ~10 years ago they were very optimistic that they would identify a handful of mutations that caused most stuttering but have been somewhat surprised & disappointed that success in identifying stuttering mutations has been pretty limited. My own personal experience is stuttering has a negative effect on “fitness” so I would expect it to disappear. Any thoughts?

  45. erica says:

    Questions:

    If a researcher(s) were to look specifically for a pathogen cause, what might that research look like? How/where to begin? With medical histories from childhood , infancy, or pre-birth ?

    Sample of two groups? Young boys (as young as toddlers) identified as exhibiting gender atypical behavior (shown to be the best predictor yet of eventual adult homosexuality) and group of those who exhibit gender typicality? Blood tests for antibodies? Medical histories? What?

    • gcochran9 says:

      There are a lot of possible approaches. Autopsy studies, looking for brain differences, would be worthwhile, especially if you could find enough cases without AIDs. Looking at discordant MZ twins ought to be fruitful. I’d look for DNA or RNA sequences that existed in one twin but not the other: that approached was useful in finding the virus that causes Kaposi’s sarcoma. You might also look for gene-expression differences in discordant MZ twins. Try MRI and CAT scans of the brain. Probably MRI, since we expose people to too much radiation already… Pretty much anything you want to try would be easier with sheep: you often get into trouble dissecting unwilling humans or subjecting them to breeding experiments, but the sheep lobby seems to be weak.

      The upcoming GWAS study is unlikely to find any one locus that has a strong effect, but it might show variants that that have a real but small effect, and that could give hints a to the mechanism. Maybe those variants congregate in certain enzyme paths.

      • erica says:

        GC:
        “Looking at discordant MZ twins ought to be fruitful.”…
        “You might also look for gene-expression differences in discordant MZ twins.
        ————————-
        I thought I remembered a reference to another twin study so I went looking–there is one in progress at UCLA where one twin is gay, the other straight.

        http://gaystudies.genetics.ucla.edu/UCLA%20Twin%20Sexual%20Orientation%20Study/Welcome.html

        The researchers claim to have found in a previous study (link below) that mothers of gay men have one of their X’s deactivated at a rate much higher than do mothers of straight sons–extreme skewing of the X. They don’t know if it’s a causation or a correlation or whatever, but I think it led to the epigenetics study they are doing now on gay/straight twin pairs. (first link)

        Extreme skewing of the X : http://escholarship.org/uc/item/863841tx#page-1

        Any thoughts? Maybe the study of discordant twins at UCLA and the one of gay brothers at Northwestern will lead to some clues.

      • Jan Verbeeren says:

        Wouldn’t it be a very easy experiment to try to infect very young male sheep with the pathogen by injecting them with an extract of the brain of adult homosexual sheep?

  46. Wait...what? says:

    “Being a cultural thing, it’s fairly easy for homosexual men to get get bored with it and turn heterosexual, or to change with just a wee bit of
    encouragement, say aversion therapy using electric shock.
    Yup.”
    Posted by: gcochran at August 18, 2003 05:52 PM

    Read on:
    http://www.gnxp.com/MT2/archives/000887.html

    • erica says:

      To Wait…what?….

      I’m not being sarcastic here; I simply don’t understand what it is you are trying to point out by linking to earlier comments on gnxp by Cochran. His point there was just as it is now, that the notion that male disinterest in females is “cultural” rather than biological is ludicrous.

      • gcochran9 says:

        I wouldn’t say that it’s utterly ridiculous. Maybe there’s something about civilization, or some aspect of civilization, that makes people crazy. You can certainly think of a lot of fitness-reducing behaviors that people show in civilization. However, most of them involve doing things that basically used to work – but with a modern twist, don’t. Men who succeed with women but have no children because of birth control are not really an anomaly, anymore than someone who likes saccharin, even though it isn’t food. If we could make replicants that looked exactly like Sean Young in Bladerunner, I suspect a lot of guys would behave in ways that didn’t result in babies…

        But homosexuality is not like that. It is not a case of pursuing a strategy that used to work.

      • whatever says:

        Dr. Cochran,
        This homosexuality is not expressed among wild ancestors of the sheep; the wild sheep, mouflon, etc. I have not heard of a homosexual male mouflon in the wild. It might be fair to say that homosexuality was none existent in the sheep before its domestication; similarly, as you say, the homosexuality is practically unknown in the untamed, undomesticated groups of H. Sapiens, predating the invention of farming, by which I mean the hunter- gathering state of the societies. The civilization is a process of acculturation and taming of our own species, a self-domestication, that likely started with the introduction of farming. Acculturation of a species is a physiological process and definitely includes loss of genes and acquiring of new traits, some of which neutral or unintended by the process. Could homosexuality in both species be an unintended side effect of the process of domestication and taming, due to a loss of genes/change of gene functions or could this domestication have made both species susceptible (to a certain degree) to homosexuality or the bug that causes it?

      • TGGP says:

        whatever, agriculture increases population density. Not surprising that it would increase disease risk among both humans and livestock.

  47. Greying Wanderer says:

    This incoming theory seems a little mad to me but after reading about bugs that make bees drown themselves who knows…

    “I see no reason to believe such transmission has to be through anal penetration”

    My understanding is AIDS spread more among homosexual men because the skin in the anus is thinner and tears more easily allowing direct transmission to the bloodstream. If so then if you were a pathogen trying to sexually transmit yourself as efficiently as possible wouldn’t making a carrier attracted to sodomy – hetero or otherwise – make sense?

    What would happen if this pathogen existed in a culture where sodomy became taboo – might it create a pressure to switch orientation to one where there was no choice of venues?

    • chozang says:

      “My understanding is AIDS spread more among homosexual men because the skin in the anus is thinner and tears more easily allowing direct transmission to the bloodstream. ”

      That is one reason. Another is promiscuity. Another is that only among male homosexuals can one be both the recipient and the injector of semen. The recipient of semen has the highest risk of contracting AIDS. Once one has the HIV virus, one can then inject semen into another homosexual, thus spreading it.

  48. Anne says:

    Cochran predicts: “I’d bet that most cases have the same cause”.

    Sean’s asks: “Do you currently believe that a pathogen responsible for causing homosexuality is spread by homosexuals?”

    Cochran’s answers: “I don’t know. It looks unlikely: there would have to a whole lot more cases of boys being molested in childhood than I know of.”

    and…Erica correctly states: “Young boys (as young as toddlers) identified as exhibiting gender atypical behavior (shown to be the best predictor yet of eventual adult homosexuality)…” and ” Most gay guys have not been contacted by a pedophile.”

    those assuming the mode of transmission is sexual may be off course

    • Greying Wanderer says:

      “those assuming the mode of transmission is sexual may be off course”

      I’m actually thinking about something similar which may or may not be related. There are heterosexual populations with a significant element who
      – are extremely promiscuous
      – are casual about coercion
      – have a penchant for sodomy
      – have a lower threshold than other groups for considering males as a suitable substitute

      all of which now strike me as possibe evidence of compulsion.

      If there’s any truth in that then the Congo would be (or will be) the world epicentre.

  49. Pingback: Cochran on Homosexuality « Secular Blood

  50. j says:

    The Congo and the Melanesian peoples would be prime candidates, yes. And Spartans and other Ancient Greeks. But paedophilia, however educational and character-forming, is not enough. The parasite has to be present in the population. And some yet unknown intermediate host, like sheep, to complete the parasite’s life cycle.

    I have a feeling that we are just before the point when everybody exclaims: “It is so obvious! I knew it all the time!” (By writing this, I’ll be able to claim that I knew it all the time. We inbred priests of the snake cult are devious like that).

  51. JK says:

    “It’s too common to be mutational pressure”
    The real question should be, do societies that are repressive of homosexuality have higher occurrence of it? In other words you would expect homosexuality to be selected against viciously and so disappear. That is unless the society is so repressive against it that the normal weeding process does not occur as closeted homosexuals end up marrying and having children so their genes (or whatever is the cause) are not weeded out as you would expect.

  52. Robert Dole says:

    What if mild androgyny in heterosexuals led to more partners? If genes that sometimes produce a feminized male (“half-gay”) are under strong enough selection, occasional overshooting (possibly still adaptive in its own right) would persist despite the obvious negative selection for nonreproductives:

    Genetic factors predisposing to homosexuality may increase mating success in heterosexuals (2008)
    “We show that psychologically masculine females and feminine men are (a) more likely to be nonheterosexual but (b), when heterosexual, have more opposite-sex sexual partners. With statistical modelling of the twin data, we show that both these relationships are partly due to pleiotropic genetic influences common to each trait. We also find a trend for heterosexuals with a nonheterosexual twin to have more opposite-sex partners than do heterosexual twin pairs. Taken together, these results suggest that genes predisposing to homosexuality may confer a mating advantage in heterosexuals, which could help explain the evolution and maintenance of homosexuality in the population.”

    http://www.sciencedirect.com/science/article/pii/S1090513808000688

    • Anne says:

      to RD: how does the fact that: “identical twins are usually discordant (~75% of the time)” play into your genetic theory?

      • Robert Dole says:

        Quite well, actually. I knew a pair of identical twins in high school. One was clearly more feminine (I even remember using that to differentiate them before I knew them well) and he turned out gay. Twins are often discordant for autism, which is generally understood to be genetic/epigenetic (i.e. not pathogen-induced). Autism and sexuality are both linked to fetal androgen exposure, which might mean that hormones in-utero partly control phenotype (a matrilineal epigenetic effect).

        Phenotype differentiation via a single fetal hormone is apparent in other eusocial species (assuming you recognize humans as eusocial):

        >> Ants turned into ‘supersoldiers’ (2012)
        “We understand a lot about how these different castes are produced during development of the ant larvae,” said Dr Abouheif. […] When a queen lays eggs, he explained, each egg can develop into a different caste depending on the environment it is in – the temperature it develops at and the nutrition it receives. But **the key to “switching” into a specific cast is controlled to a large extent by one chemical inside the eggs, which is called juvenile hormone.** […] “So if you treat any species at the right time in development, just with a hormone, you can induce the development of the supersoldier,” explained Dr Abouheif.
        “The fact that you can induce it in all these different species [that don’t naturally have that caste], means that one common ancestor of all these species had [supersoldiers].”
        http://www.bbc.co.uk/nature/16424096

        Also, monozygotic twins vary in copy number. Certain copy number variations are linked to autism, schizophrenia, bipolar disorder, and a number of other cognitive phenotypes that are individually deleterious, but are now recognized (controversially so, in some circles) as adaptive when selectively incorporated into large human groups:

        >> Copy variations in schizophrenia and bipolar disorder (2009)
        “The CNVs of interest have to be mapped more precisely and inexpensive and accurate means for genotyping them need to be implemented. In addition to SZ and BD, CNV analysis should also be a valuable tool for studying the genetics of other neuropsychiatric conditions, such as OCD, Tourette’s, and major depression, and behavioral traits, such as homosexuality, which have underlying genetic contributing factors that have been difficult to identify.”
        http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2920181/

  53. What do domestic sheep and civilized humans have in common? Bizarrely low male aggression as compared to their wild-type ancestors. How do you reduce male aggression? Feminize.

    Historically we see homosexuality become endemic among populations after many centuries of stable government, under which high male aggression is unusually counterproductive. Precisely the same kind of evolutionary pressure and result seen in… say… Jewish intelligence.

    Low twin concordance suggests that homosexuality is a risk rather than a determined outcome of feminization. Intelligence has higher twin concordance. Intelligence is not a hormonally mediated secondary sex characteristic – notoriously environment sensitive. So there’s environment stuff as well. But the genetic explanation seems a lot more parsimonious. Also, 75% discordance means 25% concordance, which isn’t low compared to the background rate.

    • Max says:

      So high male aggression is “unusually counterproductive”, therefore homosexuality i.e. not even trying to reproduce is a successful strategy?

      Homosexuality is the equivalent of committing suicide before reproducing. Any other strategy is better than this. Even if it gets you killed 99 times out of a 100, it’s a better strategy.

      Also it’s not clear at all that high male aggression is “unusually counterproductive” in civilized or state societies. Civilization and state societies often introduce winner-take-all dynamics where high male aggression, whether physical or of more invidious non-physical forms, is handsomely rewarded by allowing the men who possess it to take over the state or upper strata of the social hierarchy and become a primary germ line.

      And it’s not the same kind of evolutionary pressure that resulted in Jewish intelligence. That pressure rewarded greater intelligence with greater reproductive success. Homosexuality does not reward one with greater reproductive success.

      • Exclusive homosexuality is a risk of feminization (ie, pussification) – not a determined outcome. You can see this from the twin concordance rates if nothing else.

        Your standards for “high male aggression” are modern and civilized – ie, low. Ever heard of the Yanomamo?

      • Max says:

        Exclusive homosexuality is a risk of feminization (ie, pussification) – not a determined outcome. You can see this from the twin concordance rates if nothing else.

        You’re begging the question.

        Your standards for “high male aggression” are modern and civilized – ie, low. Ever heard of the Yanomamo?

        I don’t see how the high male aggression involved in the violent, physical takeover of state societies is “low”. Ever heard of Genghis Khan?

      • Anthony says:

        Shifting the entire distribution of “male aggression” would result in extreme events happening more frequently. If, due to social change, a slightly lower level of aggression became the reproductive optimum, you could expect to see fewer incidents of extreme violence, and more instances of very non-aggressive individuals.

        I’m not convinced that homosexuality is an extreme case of non-aggressiveness, nor of “feminization”.

        Homosexual contacts are somewhat socially constructed – in most societies through history, homosexual sex has been older, more powerful men “topping” younger and/or less powerful men, who bottom. Bottoming isn’t really voluntary, except that it becomes a social norm, and people come to expect it. Even in modern American homosexuality, possibly a majority of gay men are either tops or bottoms, rather than “versatile”, though most bottoms are voluntary. So any theory of homosexuality has to take into account these social differences.

  54. tommy says:

    Could homosexuality just be the unfortunate byproduct of selecting for, say, more beautiful women? There are probably hundreds or thousands of genes that impact masculinity or femininity. Why couldn’t some combinations of otherwise desirable genes just turn out to be dysfunctional?

  55. djinnha says:

    How is homosexuality defined here? For homosexuality to make any sense in the context defined here you’d have to assume that homosexuals don’t reproduce. Therefore homosexuality here means exclusive homosexuality and enough lack of interest in sex with women that reproduction doesn’t take place (he even gives the example of a ram not responding to a ewe in heat). That’s all fine and good, and I agree. That’s not most people’s definition of homosexuality though, and people like this account for a very small fraction of those who actually engage in homosexual behavior. Therefore the author should really clarify what he means. If he’s talking about homosexual behavior, that can take place in any number of contexts and for any number of reasons. It takes place in jails; it takes place in pederastic societies and is almost universal in antiquity, not just in the Greek and Roman world, but in the entire Orient. Good luck finding medieval Arab love poetry that’s about women. Outside the cultures inspired by the Bible, pederastic and homosexual behavior is very common. I don’t know what he’s talking about RE hunter-gatherers; it’s well-known that Melanesian tribes and many Amazonian tribes practice it, and it’s very common among African tribes as well. So there seems to be a bait-and-switch going on here. Obviously men who engage in homosexual behavior of this kind, which is heavily geared to pederasty, also reproduce and also like women (in fact it has been argued that boys are prized for their feminine qualities). On the other hand it may be true that a tiny fraction of men who engage in homosexual behavior are exclusive homosexuals. Such men, however, also exhibit other traits, like effeminacy and a few other peculiar qualities, and in many cases they even look different, in terms of face structure and so on. Why couldn’t it be, and I mean this in general by the way, that homosexual behavior as such is nothing more than a symptom or side effect and that it can have several causes? The author needs to make his definition more precise, but it should go without saying that what he is discussing here doesn’t fit most people’s definition of homosexual, as most people would consider ancient Greek or modern Arab or Afghan sexual behavior to be “homosexual”; not to speak of the fact that there are many men in Western societies as well who are married and have children but enjoy sex with men on the side from time to time (this is especially common among lower-class men and “down-low” blacks). So anyway, I’d agree in general that the very small number of exclusive gays need to be explained in some other way, but the author needs to make this clear. In general “homosexuality” is not a useful category, the word didn’t even exist before the 19th century and most societies don’t define sex in homosexual vs. heterosexual terms.

    I would say in the small percentage of homosexuals that are exclusive, social or psychological explanations are much more convincing…the root cause is something else that leads to a more generalized femininity or aversion to women or whatever, and homosexuality is just one of the side effects of this. Often homosexuals have many other perversions as well.

    • Tom says:

      That’s not most people’s definition of homosexuality though, and people like this account for a very small fraction of those who actually engage in homosexual behavior.

      Would my dog humping my leg count as homosexual behavior? What about masturbation? When a man masturbates, he is using a male hand.

      • djinnha says:

        Tom–
        I explained this in some detail, do you read? Even if you cure the very small percentage of exclusive homosexuals you will not get rid of most homosexual behavior–not masturbation, but acts of sex between men, or between men and adolescents. In much of the third world acts of sex between men are very common, and they’re also common among straight working class guys and black guys in the US. They’re common in prisons. Historically pederasty was very popular and in some cases socially sanctioned in many societies across time and space, at all levels of development. These men still reproduced though, they married women and had children. “Women are for children, boys are for pleasure.” What definition of homosexuality does the author have? He seems to have accepted the homosexuals’ own definition of themselves as a discrete group that is exclusively gay, etc.

    • erica says:

      djinnha,

      GC is speaking of obligate, not facultative homosexuality.

      Think of men who have no lust for women. They may have sex with women, may even be married with children, but their sexual lust and romantic attractions are for men. They fantasize about men in order to perform with a female. They masturbate to images of men….clear enough?

      Go this site http://gc.homeunix.net/ to read other articles, comments from him about the subject if you can’t put 2 and 2 together about what he said in this post.

      • djinnha says:

        Yes I figured as much…but as I keep saying, exclusive homosexuals account for only a very small fraction of homosexual behavior. It’s not clear why he focuses on them, since curing them obviously won’t “cure” homosexuality in general. This is a kind of bait and switch because most of the readers probably think that if you find this cure, then homosexuality will go away, which isn’t the case. Further, if childlessness as a result of male lack of interest in women is the issue, then there are many causes for this such as a variety of other perversions, asexuality, depression, religious conviction, and so on. Are ascetic religious sects actually just a cover for a parasitic infection and is the Pope infected? In fact it may be that exclusive homosexuals are actually something else, which I already said…in other words that homosexual behavior may only be a symptom of a deeper psychological orientation. Aversion to women, for example, seems more important, and deserves some explanation in this case. If GC was right that this was a parasite similar to the mouse thing, you would still expect them to be attracted to women…I assume that the infected mouse is still attracted to female mice, not just to cat urine (but I’m not sure). GC’s theory doesn’t make sense for this reason, because he focuses on the homosexuality, when in fact the homosexuality is probably a side effect of something else in the case of exclusive homosexuals.

        I would say an evolutionary explanation for why homosexual behavior in general takes place would be a lot more interesting…but that’s not what the author is providing in this case. Why is pederasty so common historically in human societies? This phenomenon is much more common than exclusive homosexuality and deserves some explanation…but obviously GC isn’t explaining this much more important and frequent phenomenon, as you yourself admit. Were ancient Greeks, Romans, the whole medieval near East, medieval Japan, the modern Middle East and Afghanistan, plus various tribes ranging from the Amazon to Africa to the south Pacific to pre-Christian temperate Europe (see the Celts) were all these infected in mass for preferring boys to their wives? Or is it much more likely that pederasty, being so common across so many cultures, actually does serve some evolutionary purpose.

      • Tom says:

        Why is pederasty so common historically in human societies? This phenomenon is much more common than exclusive homosexuality and deserves some explanation…but obviously GC isn’t explaining this much more important and frequent phenomenon

        Part of Cochran’s germ theory argument is that it’s unlikely to be a genetic disease because it’s more common and old than genetic diseases. So its frequency and history isn’t ignored. They’re some of the major considerations.

    • @djinnha

      Your post is irrelevant to the topic.

      Maybe some men are infected with the bug… and become asexual.
      Maybe some other men are infected with the bug… and nothing happens.
      Maybe some other men are infected with the bug… and stay heterosexuals but start to prefer anal sex.
      Maybe some other men are infected with the bug… and become bisexual.
      Maybe some other men are infected with the bug… and become purely homosexual.

      If it’s a bug, then science should identify the bug, find an anti-bug method and then we know what the bug does.

      Your post “how do you define homosexuality?” is irrelevant, just as would be “define schizophrenia accurately, before talking about bugs”.

  56. djinnha says:

    To clarify something: even if the author is right and you can cure the 0.5% or less of men who are actually exclusive homosexuals, this will not get rid of homosexual behavior. That will remain more or less a constant, and more prevalent in some societies than others based on local custom. But most homosexual behavior right now, not to speak of in history, is not taking place between exclusive homosexuals.

  57. Julian O'Dea says:

    I had a couple of hacks at this problem a few years ago:

    http://julianodea.blogspot.com.au/2006/07/is-homosexuality-due-to-genetic.html

    Sibling conflict?

  58. j says:

    Regarding how to start looking seriously for the micro-organism causing homosexuality, the saliva, semen, smegma, etc. of pederasts could be studied.

  59. Pingback: Is Homosexuality a Disease? « Johann Happolati

  60. Tom says:

    When a single, childless man commits suicide, nobody says that it was “genetic” as in a behavior that was directly selected for since such a claim is absurd on its face.

    Nobody says that it’s genetic and evolved as a form of altruism, arguing something like that by committing suicide he helps his siblings inherit more money and thus have more kids. There doesn’t seem to be much evidence for this, and it would have to override the large fitness cost of the suicide. It isn’t something that might be more obviously plausible like elderly Eskimos committing suicide at an old age after they’ve had kids and grandkids, in a Malthusian environment where one less mouth to feed might matter a lot.

    When they say it’s genetic in this case, what they seem to mean is something like they’ve evolved to have a dour disposition because in previous environments a dour disposition meant reproductive success. But if a dour disposition is what lead to reproductive success, then it’s hard to believe that that is the main cause of doing the opposite and that therefore it is “genetic” in that sense.

    Homosexuality seems analogous to this.

    • djinnha says:

      Suicide is definitely not “genetic.” But suicide has a wide variety of causes. What GC is doing here is the analogue of lumping in all kinds of suicides, and saying that they’re caused by a parasite. That makes less sense than a genetic explanation. But you’re right that neither explanation makes sense. You have to distinguish between the different kinds of suicide and state which you’re explaining. GC is doing the analogy of claiming that because a small fraction of suicides may be caused by a parasite, that if you cure this, you will prevent all suicide.

      • erica says:

        djinnha,

        Obligate homosexuality, it would seem, is about 2%-3%, with a much higher concentration of such in cities like SF.

        When you say, that what “GC is doing here is the analogue of lumping in all kinds of suicides, and saying that they’re caused by a parasite” it suggests you’ve not actually read what he has written either in this post or in others.

        When you say he is “doing the analogy of claiming that because a small fraction of suicides may be caused by a parasite, that if you cure this, you will prevent all suicide” I can’t help wondering just what it is you HAVE been reading.

        .

      • Tom says:

        I specified suicide by a single, childless male. As opposed to suicide by an elderly person with a family, children, grandkids, etc. in a Malthusian situation.

        The pathogen theory does make sense, much better than claims that it’s “genetic”. That was my point.

        Also I don’t see why it’s necessarily implausible that even men who are just gay on the side are afflicted with the pathogen. Not everybody is affected the same way by a pathogen, some are totally immune, while others are hurt by it to varying degrees.

      • Tom says:

        I specified suicide by a single, childless male. As opposed to suicide by an elderly person with a family, children, grandkids, in a Malthusian situation.

        The pathogen theory does make sense, much better than claims that it’s “genetic”. That was my point.

        Also I don’t see why it’s necessarily implausible that even men who are just gay on the side are afflicted with the pathogen. Not everybody is affected the same way by a pathogen, some are totally immune, while others are hurt by it to varying degrees.

  61. Pingback: Further Thoughts on Homosexuality « Johann Happolati

  62. Greying Wanderer says:

    Another probably mad thought on this or rather the more general case of sexual behaviour possibly being modified by pathogens – has there ever been studies or reports of sexual behaviour being changed accidentally by medical treatments like antibiotics or chemo-therapy?

  63. j says:

    Sure. They are thousands of them. But I most like the experiments of electrical stimulation of pleasure centers of brains of female students. Poor girls fell hopelessly in love with the experimenter. Dont do it at home.

  64. Pingback: The Death Match between the Genes and the Pathogens

  65. djinnha says:

    Tom said:
    “Part of Cochran’s germ theory argument is that it’s unlikely to be a genetic disease because it’s more common and old than genetic diseases. So its frequency and history isn’t ignored. They’re some of the major considerations.”

    I say:
    The simpler explanation for something that is that frequent, universal, and old, is that it’s a natural human behavior. You might as well say that the desire to sing music is caused by a pathogen. A cultural Muslim who disapproves of music may very well come up with that idea one day. Cochran’s “pathogen” hypothesis only makes sense in the context of homosexual behavior somehow harming reproductive success. But the most frequent homosexual behavior is pederasty or “predatory bisexuality” like existed and exists in the cases I mentioned, and the men who engage in it still reproduce. It’s more likely that homosexual behavior in general is as “genetic” as any number of other universal human activities, and that it serves some natural purpose or has some genetic basis. The mistake is to think of it as a disorder.

    If the sexual instinct were so specialized as to only be turned on by very specific female forms by the way, the human race would have died out a long time ago. A male rooster will mate with anything remotely resembling a hen form, even an oval piece of wood. It may be that sexual attraction to adolescent boys has the same cause. Conversely, it may be that pederastic relations serve some eusocial purpose. Pederasty in no way negatively affects birth rate. If anything, pederastic societies like Afghanistan have far higher birth rates today than heterosexual societies do. Homosexuality is rampant in subsaharan Africa, but the birth rate is through the roof. It may be that homosexual behavior is just a side effect of hypersexualized male behavior. As such in fact lack of pederasty and “predatory bisexuality” may be a sign that something is wrong in a society, that the men are becoming less manly and sexually bold, etc.

    The bait and switch that Cochran is doing is that in fact he never really defines what homosexuality means…if he means to restrict it to modern Western-style exclusive homosexuals, or if he means that it covers all homosexual behavior. To dispute your point by the way, modern Western homosexuality is unheard of in human history. There were always a small minority of men who were seen as primarily effeminate or passive though; the connection to homosexual behavior is, however, only incidental. That is what Cochran should have focused on, if history were to be taken as a guide. But the behavior of this small percentage of men, while interesting, still wouldn’t explain the most frequent kind of homosexual behavior. You yourself seem to confuse the two.

    • Am I reading this correctly, is a spergy HBD kook who probably still retains his virginity and lives as a kept hermaphrodite on a curated, bully-free university campus attempting to hold forth on manliness? I wish I were there so I could laugh in your face.

  66. Nolte says:

    Diarrhea is something that is even more frequent, universal, and old than homosexuality. Most people have had diarrhea some time in the course of their lives. This doesn’t mean that diarrhea isn’t caused by pathogens.

    • djinnha says:

      Diarrhea impairs function and can lead to death. Pederasty not so much. Again you and Cochran are showing a cultural bias…you think pederasty is “bad” therefore it could be caused by a pathogen. On the other hand, pederasty could be like music, or masturbation, or any number of other human activities that have a genetic basis, but where there is no reason to think they’re caused by pathogens.

      Pederasty is universal. Exclusive male homosexuality is confined to a very small percentage of the population. Which is Cochran talking about?

      • Nolte says:

        Diarrhea can also help you live by flushing out whatever’s bothering you. Pederasty and any form of wanton sex can lead to impairment and death. Sexual activity and intimate contact can involve all kinds of vectors. Also a pederast might get his skull caved in or be stomped to death by the boy’s father or male relatives.

        Diarrhea isn’t necessarily “bad”. There is coprophilia. Some people enjoy it like music, or masturbation, or any number of other human activities. Diarrhea has a genetic basis; it involves body parts and functions that are ultimately coded by genes. This doesn’t mean an instance of diarrhea isn’t caused by pathogens. Any kind of sexual activity also involves body parts and functions that are ultimately coded by genes. This doesn’t mean an instance of sexual activity, or particular type of sexual activity, isn’t caused by pathogens. You can vomit by sticking your fingers down your throat, or by catching stomach flu. Vomiting has a “genetic basis”; it involves body parts and functions that are ultimately coded by genes. This doesn’t mean an instance of vomiting can’t be caused by pathogens.

        Pederasty is universal?

        Are you one? Is anybody you know one?

        I’m not, nor is anyone I know.

        I’ve had diarrhea though. And pretty much everyone I know has had diarrhea.

        Also note that when you claim some form of homosexuality is more common than generally believed, you’re not really contradicting Cochran because that’s part of his argument.

  67. Nolte says:

    There could be a “generalized form of” parasitic castration caused by the pathogen or pathogens involved. In ordinary parasitic castration the parasite itself renders the host infertile so as to route reproductive metabolism to feed the parasite.

    Female farming increases harem size thereby bifurcating the males into a few alphas and many sneaky betas, some of whom are bisexual. This is horizontal transmission heaven for the evolution of virulence of all kinds. HIV, for instance, is so sophisticated that many doubt it could have naturally evolved! But even they under-estimate its virulence as it is likely to differentially attack the amygdala which is a known metabolic pathway to induce promiscuity (Klüver-Bucy Syndrome). It is easy to imagine all manner of sexual “variations” arising as extended phenotypes in the “independent female” situation.

    Vertical transmission is oppositional to horizontal transmission in terms of coadaptation, so I would expect that once a pathogen evolved that induced homosexuality — thereby selecting out the susceptible male population — the remaining male population would be in vertical transmission heaven. Cook for the required number of generations, export to a monogamous culture and its time to start rationalizing all those strange limbic impulses in “the arts”!

    • djinnha says:

      All evidence points to “alphas” in polygamous societies having also a harem of boys and often preferring boys to girls for sex. In these polygamous societies it is also common for a conquering tribe to rape the women and the men in a conquered tribe and to take the most attractive lads as sex slaves, as happened e.g. whenever the Turks conquered anyone. Throughout the medieval Orient love poetry is about boys…those were poems for and about alphas, not betas.

      Lack of historical knowledge leads to bad evolutionary psychology.

  68. djinnha says:

    Again my point is that if Cochran wants to limit his comments to modern exclusive homosexuals as another poster implied, then he should say so, but this accounts for only a very small fraction of actual homosexual behavior. Most homosexual behavior now and historically would remain unexplained. It does deserve an explanation, but a pathogen in the more general case makes no sense. It would make as much sense as suspecting a pathogenic origin of singing, or masturbation. The only basis Cochran had to suspect a pathogen origin is that obviously exclusive homosexuals incur a great cost: they’re not turned on by women and don’t reproduce. But this isn’t the case for most men who engage in homosexual acts in general. They still have attraction to women, and still reproduce. Pederastic Afghanistan has a far higher birth rate than Western non-pederastic societies. Does pederasty have possible costs…sure…so does celibacy, married life, etc.; that’s irrelevant.

    It may be that men who like to fuck, and are free to fuck what they want, will fuck pretty much anything. How about that as an explanation for homosexual behavior in general.

    Nolte I did understand your comment, but you don’t know history. In polygamous societies the alphas who hoard women also hoard boys and often prefer them for sex. They have harems of boys for example. It’s not something that’s caused by lack of access to females, as you imply. Furthermore if you take e.g. monogamous and pederastic ancient Greece, in ancient Greece pederasty was fashionable among the elite who had plenty of access to female prostitutes and slaves. And this was a monogamous society, again. So your theory of how it could have spread doesn’t make sense because those societies you’re thinking of don’t actually work like that.

    Rather than accept your convoluted theory of a pathogenic origin it’s more likely that modern “artsy” effeminate and exclusive homosexuals are actually “artsy” and effeminate first, and homosexual second, i.e., the homosexuality is only a side effect of a more fundamental personality trait.

    Diarrhea is clearly a disease, and has always been recognized as such. Pederasty is universal in human history and was celebrated in many cultures. I’m not aware of any historical cultures that celebrated diarrhea or thought it was anything but bad. But since you make that argument, what basis do you have to suspect that anything at all is caused by a bug? That’s what I’m asking. What is it about pederasty (the most ubiquitous form of homosexual behavior by far historically) that causes you to think it’s caused by a pathogen, but not singing, or masturbation, etc.; there is no evidence that it has any adverse effect on reproductive success, in fact there are hints at the opposite.

    • j says:

      Has pederasty a positive effect on reproductive success? May be, could you elaborate pls.?

    • erica says:

      “What is it about pederasty (the most ubiquitous form of homosexual behavior by far historically) that causes you to think it’s caused by a pathogen, but not singing….”

      What’s with the constant mentioning of the singing of birds as your analogy? In most instances, how long and well a male bird sings influences how well the little lady birds react to him. IOWs, it’s an attraction thing, a mating thing, and oh, yeah….mating leads to reproduction.

      Your assertion seems to be that because in some cultures powerful men practiced pederasty, it’s therefore insignificant that there were/are men who lack/lacked interest in women. Doesn’t compute.

      The pederasty practices are, however, interesting., and there’s much about them we don’t know. A topical case in our country right now is the so-called “pedophilia” case of Jerry What’s His Name, the former Penn State football coach who, over a number of years, practiced what has to be called pederasty since he saw himself as a mentor and lover of these boys, a groomer of men, not as a stalker or as a rapist. The “pedophile” label is simply a legal one. He is, it appears, soley attracted to young males: all his own kids are adopted and it appears he has no interest in women, although he is married. There are a lot of these pederasts (pedophiles) in our society.

      Mate choice here is what is in question: whether we call this man homosexual (since, after all, he seems to have no attraction for females of any age), or a pederast, or both, is inconsequential when we consider that his mate choice is screwed up in terms of fitness. I have no problem believing some pederasts manage to produce a kid with a woman if for no other reason than escaping detection. When I look up the names and addresses of sex offenders in my neighborhood/area and see their crimes listed, I see several “pederasts” among them. Their behavior is not analogous to the singing of the male bird.

      You sound a lot like like crazy old Henry Hay who kept alive his hope for the man-boy love thing, and was convinced, I am sure, that he was one of nature’s songbirds,

    • Nolte says:

      You did not understand the comment.

      I’m aware of historical accounts of pederasty.

      I’m also aware of polygamous societies. Your claim that large and wide scale pederasty characterizes every polygamous society is false.

      It’s not my theory, it’s Cochran’s. And it’s a lot less convoluted than the confused ideas you’re proposing here.

      There are subcultures that celebrate diarrhea.

      It’s easy to see how pederasty and other form of wanton sex might be dangerous. Sexual activity and intimate contact can introduce many vectors. Also a pederast might get his skull caved in or be stomped to death by the boy’s father or male relatives.

      Read Cochran and Ewald to see the reasoning behind suspecting pathogens.

      And it’s really sloppy thinking to class pederasty with music and masturbation.

    • Anthony says:

      On the other hand, the fact that “exclusive” and or more egalitarian homosexuality is a relatively modern phenomenon, limited to some societies, would seem to make it *more* likely that such behavior is pathogenic, even while leading to the conclusion that pederastic homosexuality is not pathogenic.

  69. djinnha says:

    You reveal your bias when you refer to pederasty as “wanton sex.” Your problem, and Cochran’s, is a culturally-based moral bias against pederasty, based on which you suspect that it’s a disease. But you fail to show that it incurs any more or less reproductive cost than exclusive heterosexuality. A girl’s relatives, or your rivals, can also stomp your head in; hetereosexual sex can and often is wanton. Not all pederastic sex even involves penetration by the way. In fact it’s no more or less wanton than exclusive heterosexuality as such, and many cultures considered sex with women to be more “wanton” than sex with men. It’s only easy for you to make this claim because you want to muddy the waters and claim that modern exclusive homos, who don’t have children, are representative of homosexual behavior in general. But they’re not, and despite your stories that pederasty could give you some disadvantages, what you say can just as well apply to exclusive heterosexuality; anyway, they’re just stories or speculations…you have no evidence that pederasty costs you anything, and in fact I gave you several examples of very high-birthrate pederastic societies.

    Again, I ask, what is your basis for even suspecting that something is caused by a pathogen? A certain type of “scientific” Muslim who disapproves of music may well speculate that singing is caused by a pathogen.

    The sleight of hand lies in conflating modern exclusive homosexuality and homosexual behavior in general. Without this hand-waving, Cochran’s theory is of little value, because even if modern effeminate/exclusive homos are driven by a bug, they represent a very small subset of homosexuality in general and of what most people consider homosexual behavior. Other posters saw this by the way…they realize Cochran’s theory makes no sense for pederasty or predatory bisexuality, etc., which is by far more frequent, and apparently does not affect reproductive success in the least.

  70. djinnha says:

    Erica…
    I didn’t mention birds, you did. I mentioned human singing. What evolutionary purpose does it serve? Maybe it does serve a purpose. Or maybe it’s caused by a pathogen…according to Cochran, that makes sense. It makes about as much sense to consider pederasty or homosexual behavior as caused by a pathogen. The truth is you confuse things, there is simply no evidence that someone who engages in homosexual behavior (of which pederasty is historically the most common) incurs any reproductive cost. In some cultures it’s part of initiation rites. Cochran is wrong about it being unknown in tribal societies, it’s practiced in Melanesian tribes, in the Amazon, etc., as well as in herding and agricultural societies. It’s not a matter of words no…such men also marry and have children. There is a common phrase known in the Middle East, “women are for children, boys are for pleasure.” They have higher birthrates than we do.

    You know, it’s possible that as with music, storytelling, and masturbation, men might just enjoy this…they might enjoy fucking other males who are young and have some feminine features, or they may enjoy fucking another man as a part of domination or just for the hell of it. Or there may be in fact an evolutionary advantage to pederasty in particular, it may serve some eusocial purpose. But it’s very dishonest to conflate homosexual behavior in general with modern exclusive homosexuality in particular, which, you are right, does include a lack of attraction to women.

    I would go so far as to say, at least in the modern world, as you go from society to society, the less likely the AVERAGE male is to be willing to engage in a homosexual encounter, the lower the birthrate. Societies where homosexual behavior is rampant like Afghanistan, subsaharan Africa, and until recently the Arab cultures, or for example Brazil and many Latin American countries, where it’s not considered gay if you’re “on top,” have far higher birthrates than places where people think homosexual behavior is as such something not to engage in. It may be that the male sexual instinct is to penetrate or dominate without being very discriminating about the object. I said above in fact that if it were so specialized as to only be directed to a certain female form, the human race would have died out a long time ago. The male rooster will try to mate even with an oval piece of wood.

    Sexual dysfunction in the modern world is a far more interesting topic therefore than focusing only on homosexuality as such. 15% of American men who reach the age of 40 are virgins, and this figure may well be higher in Western Europe and East Asia. Are these men infected by a bug, or is it just the unfortunate convergence of certain personality traits with unique social pressures of advanced modern societies? I would count modern homosexuality as a subset of modern sexual dysfunction in general. It has next to nothing to do with ancient pederasty or predatory bisexuality as you find it in the third world today (or even among American blacks and often among working-class men). However, this latter kind of behavior, being far more frequent and common than exclusive homo, does deserve an explanation. It’s just that Cochran doesn’t provide it.

  71. erica says:

    djinnha,

    The bottom line is you seem to feel that the number of males who are never sexually aroused by women (in their dreams or in reality) is so insignificant, so minute, that someone concerned with natural selection/evolution and fitness ought not to trouble himself with it, ought not to proffer an explanation for it. ( I might add you seem equally uninterested in how many of these males as youngsters exhibit behavior at very early ages which is predictive of their ultimate sexual disinterest in females, in spite of their anatomy which comes fully equipped with working sperm-delivery systems.) GC has argued their numbers are too high to be chance mutations.

    You call this “human nature.”

    You are not persuasive.

  72. Nolte says:

    If you don’t like the term “wanton sex”, you can call it something else. You can call it non-reproductive sex, or recreational sex, etc. My point still stands. Pederasty and other forms of recreational sex can be dangerous.

    I’m not sure what exactly constitutes a “pederastic” society.

    A high-birthrate pederastic society tells you nothing about differential male fertility within those societies.

    If you want to understand the reasoning behind suspecting pathogens, read Cochran and Ewald.

    You haven’t shown any evidence that pederasty, predatory bisexuality, etc. don’t affect reproductive success. You haven’t shown any evidence that turning to pederasty, predatory bisexuality, etc. doesn’t rise with lower access to women and thus less reproductive success.

  73. Nolte says:

    It may be that the male sexual instinct is to penetrate or dominate without being very discriminating about the object. I said above in fact that if it were so specialized as to only be directed to a certain female form, the human race would have died out a long time ago. The male rooster will try to mate even with an oval piece of wood.

    If you’re going to classify the homosexual activity you’re talking about in this way, then it’s hard to see how it’s different from masturbation, or having sex with an animal or some object. You’re suggesting that there isn’t really attraction or desire there, but just desire for sexual release. If access to women were readily available, they would turn to women. But since they’re not, they can’t and resort to other means.

    Note that polygynous societies exclude many men from access to women and mating opportunities. Pederasty, predatory bisexuality, etc. in this context may lead to lower reproductive success, or it may be an indication of lower reproductive success.

  74. djinnha says:

    No this is not true. When men have a choice, free from women’s domination (e.g., feminism today) or social sanction/custom (as exists pretty much only in Christianity and Judaism) they actually prefer boys for sex and especially romance. This includes men with access to women for sex, and especially these men actually. That’s why pederasty was so common among the Greek upper class that had unlimited access to courtesans and slave girls; it’s also why it was so common among medieval Arab, Persian, etc., aristocrats who had access to the same. It is only because of the weight of accumulated Christian and post-Christian anti-pederastic morality that you all have difficulty conceiving of this. These men had far more access to a variety of women’s vaginas than even the most successful modern “player” does, but they still preferred boys for sex and romance.

    It is only in its period of decline that Greek taste turned heterosexual.

    • When men have a choice, free from women’s domination (e.g., feminism today) or social sanction/custom (as exists pretty much only in Christianity and Judaism) they actually prefer boys for sex and especially romance.

      You nearly make it sound as if it’s the heterosexuals who are infected with some mind altering bug.

      And excuse me, but if your theory would be true: Wouldn’t men nowadays download only gay porn if they could?

  75. erica says:

    @djinnha
    “When men have a choice, free from women’s domination (e.g., feminism today) or social sanction/custom (as exists pretty much only in Christianity and Judaism) they actually prefer boys for sex and especially romance. ”

    Yep, this statement puts the exclamation mark on all your other posts–not only do men “prefer boys for sex” but for “especially romance” too. Yep, a member of NAMBLA or at least one who is indeed just as sick. The bug infecting you is especially virulent.

  76. utrecht says:

    Homosexual sex need not be a mere replacement for heterosexual. Some of the manliest men, with most access to women, still enjoy fucking another man and making him their bitch. There is something about putting it to another guy and dominating him that is more exciting than just with a woman. But you Americans are all passive homos and will never understand this. You just want caresses from your women, you are soft.

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  78. Julian O'Dea says:

    A good reference for culturally-approved homosexual behaviour:

  79. erica says:

    Dr. Cochran, I don’t know if you’re still checking in on this thread, but I remembered something I have wanted to ask you.

    Whenever this subject comes up, many people claim that high levels of stress during pregnancy is a likely cause of male homosexuality, and as evidence they frequently point to studies of pregnant women who survived the bombing of Dresden. They claim these studies (or perhaps “a study”) showed a higher % of males born to these women wound up homosexual than would be expected in a population of women who had not experienced such a stressful event.

    Is this an urban legend? Do such studies exist, and if so, what were their results, for I can’t find any source for them. In fact, I think I recall your having said on another blog once that there is no evidence that stress during pregnancy plays a part in the eventuality of a male being homosexual, but I may have dreamed that and don’t want to put words in your mouth.

    • gcochran9 says:

      Try googling ” +homosexuality +stress +germany ” on Google Scholar. You’ll see some papers by Dorner claiming this, and then several nonreplications. I think there’s nothing to it. By the way, the concept of ‘stress’ has been remarkably unproductive.

  80. erica says:

    Thanks for the response. Will do.
    Yes, I did think I recalled your saying that stress is often labeled the cause of many maladies, yet when examined more closely, turns out not to be the case.

  81. MK says:

    I am bisexual and have had sex and long term relationships with both men and women. I have had 25 female sexual partners and 19 male sexual partners. I have no idea what causes my bisexuality. But I do know the effects. I am an actor and have often been told I have a “presence” ie. charisma. This Charisma naturally attracts people to me and I have responded sexually. I have known many bisexual men most are closeted and invisible as their homosexuality would cancel out their heterosexuality if they were open about it. Oscar Wilde called his own sexuality “opportunistic”. The problem in contemporary culture is we catagorize “gay” and “straight” behavior to such a degree that real bisexual behavior becomes quickly erased. But let’s look at a genetic possibility. If there was a “gay gene” is it possible that bisexual men propagated that gene? Many bisexual men do not express their bisexuality as I know many “straight” men who confide in me of their homoerotic desires. Without condems, safe sex, and coitus interuptus I would have fathered as many as 40 different children. The bisexual question is not considered because gay and straight culture says we don’t exist but we very much do.

    • bisexuals exist in very small numbers but because you are an actor reputed to be bisexual you have a case of confirmation bias (acting world is now so infested with gays that it repels straight men)

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  83. Filip says:

    Dr.Cochran how you explain the research of Dr.Simon LeVay of the role of INAH3 nucleus of the anterior hypothalamus.

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  85. 141 says:

    I’m of the opinion it’s merely Classical Conditioning. I read an article a while back about a male hooker from Hollywood that said he had sex with Cary Grant and other leading men. He said that he was molested by a priest when he was young, but he went with it and kept going back because it felt good.

    At first, Pavlov’s dogs didn’t salivate at the ring of the bell, but after a few days of food being brought right after the sound of the bell, their subconscious mind anticipated the food and thus salivated at the bell.

    In the the case of Homosexuality, the homosexuals are the dogs, other men are the bells, and sex is the food.

    Because the mind has been trained to be aroused at the sight or thought of men, the subject thinks he was born gay, and rationalizes his behavior accordingly.

    Also of interest is the phenomena of pedophilia VICTIMS becoming offenders in adulthood.

    I also recently read a study that sexual arousal decreases the disgust response.

  86. Philippe Borin says:

    Innate homosexual theory is impossible.Ais syndrome theory is daft.Prenatal testosterone has no role in sexual orientation.Ais wich is a genetic disorder in SRY region in Y chromosome.Some studies have shown that the chromosomes involved in the differentiation of the brain before chormones.If a person is not exposed to hormones there will be disturbances in secondary and primary
    sexual characteristics not in sexual orientation.After LeVay study William Byne and colleagues showed no difference in the number of cells in INAH3 region.And in the number of cells is the diference between male and female INAH3 region.The problem is that each measured volume not the cell number.And the volume may depend on many other factors.The SCN plays no role in sexual attraction and has no difference bethween number of the cells in male and female brains.Has no difference in the volume and number of the cells in the other regions:INAH1,2,4. The research by Allen ang Gorsky is not confirmed by Lasco et all.Prenatal migration of newly formed neurons is guided by glial cells and testosterone has no role in this process.I think homosexuality is a secondary manifestation of something else.But i don’t know what,maybe glial cells may play an unexpectedly large role.

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  88. i’m gay myself and i think this is a reasonable enough assertion but has there been any evidence so far to go any way to prove this? or any hypothesis over what the cause may be?

  89. Anthony says:

    I have just one question for Mr. Cochran. Your theory sounds plausible, but I wonder, what’s your take on black swans, who are allegedly 1/4 homosexual (in males), obviously in orientation, not just casual behavior? I’m really interested about this.

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  99. erica says:

    Just when we think we pretty much understand how t. gondii (or other parasites) work, we find out we don’t. Hmmm. Makes one wonder if it still could be the culprit:

    http://www.sciencedaily.com/releases/2013/09/130918181110.htm

    • erica says:

      Here’s the paper: http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0075246

      “Surprisingly, we found that infection with the attenuated Type I parasite results in sustained loss of aversion at times post infection when neither parasite nor ongoing brain inflammation were detectable. This suggests that T. gondii-mediated interruption of mouse innate aversion toward cat urine may occur during early acute infection in a permanent manner, not requiring persistence of parasite cysts or continuing brain inflammation.”

  100. Jim says:

    “… make you wonder if the human brain really does exist to cool the blood.”

    Wouldn’t fins like some lizards have be easier from an evolutionary stand point? Or elephant ears. Just think you could save 20% of the energy that the brain consumes.

  101. Jim says:

    “rubella vaccine dealt a heavy blow to deaf culture by cutting the number of congenitally deaf children in half. .

    Isn’t that just too damn bad.”

    Actually deaf people have gone to court to try to stop parents from having doctors perform operations on their babies or you children to enable them to hear.

    They do so because they fear the demise of deaf culture.

    Wish I had a link for you.

  102. Anonymous says:

    Mike Bailey is a washed up fame-whore with no real academic merit and you two don’t have the credentials to even be writing about this on a blog. Optical physics and anthropology? How about you leave science to the scientists.

  103. thecivilizationalist says:

    Homosexuality and paedophilia are inter-related and there is an evolutionary theory which explains their linkages – http://humancivilizations.wordpress.com/2014/01/07/male-homosexuality-as-a-sexual-competition-reduction-mechanism/

    • JayMan says:

      While Dr. Cochran might tell you himself, the “imprinting” idea is complete rubbish. Not only is there not any good evidence that sexual orientation can be affected that way, has it occurred these individuals that, even if there was such a vulnerability in men – itself a stretch – there would be a strong selective pressure against it?

      See here.

    • JayMan says:

      Additionally, I had a lengthy discussion on why imprinting just does not work at my blog. See here.

  104. ANONYMOUS says:

    Perhaps it is supported by a virus/bacteria, but after that it is off to the races. Homosexuality assumes the role of an aristocratic meme in the Cultural Marxist theocracies of the West. To quote a democratic operative “gays are the new Jews.” Although homosexuality is more common on the poor, the wealthiest class of Americans are gay. They are entitled to litigation benefits, cultural support, a distinct subgroup w/identity, tax benefits through marriage, media support etc. In other words, dysfunction assumes the norm if it is accepted by the ruling classes. It is common to be denigrated at elite hard left colleges (Columbia U) for failing to experiment with homosexuality. Homosexuals dominate the elite and culture (Bill Buckley’s homintern).

    In other words, culture and bacteria are interwoven. Bacteria influence our culture (such as religious objections to pork, homosexuality, promiscuity, etc). Was Mohammed influenced by some infection inducing madness and is Islam the result?

    Historically, cultures evolved to deal with homosexuality as pendastry. Barack Obama was a typical example with Frank Marshall Davis providing the support for his meteoric ascendency. Pendastry was an effective means to help young boys climb the social ladder through a “mentorship” relationship with adults. Although this seems odd, communities of homosexuals practicing distinct lifestyles and sleeping with 1000 men is odder and a Cultural Marxist maladaption designed for maximum chaos.

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  109. Clayton says:

    Homosexuality is quite common in shaman culture but if you see Native American or Inuit are rarely being Two Spirits? because that Christians hostile or oppose them.

    And I read some comments say about HIV/AIDS for homosexual people is false. One reason is circumcision vs uncircumcision issues! I read some news says that circumcision heterosexual men can reduce to HIV and uncircumcision hetero men are high rate of HI in Africa but opposite to uncut gay men is lowest rate of HIV than cut gay is quite higher rate of HIV in America/Canada or other countries

    WHAT? thats weird

  110. Kjersleif says:

    I’m homosexual (with strong transsexual tendencies), and I do think it’s a very interesting theory.
    But I have a question..

    Do you have any theories or ideas about the causes of “sexual stance” among homosexuals? Most homosexuals seem to have a tendency to be either “active” (giving) or “passive” (receiving). (Though, there are also many that are flexible.)
    What could be the cause of these preferences?

    • Kjersleif says:

      I mean, what would be a pathogen’s incentive to create these preferences? Causing “active” promiscuity is obviously logical, to maximize distribution of the pathogen.. But why on earth would a pathogen influence its host with a “passive”, receiving preference?

  111. Kjersleif says:

    Also.. Why would a pathogen limit the host to a specific sexual preference? If anything, you’d assume a pathogen that wants to be distributed, would make the host pansexual?

  112. Kjersleif says:

    (I’ve summarized all my posts into one post. Please delete my other posts if you want to avoid the clutter.)

    I’m homosexual (with strong transsexual tendencies), and I do think it’s a very interesting theory.
    But I have a few questions..

    Do you have any theories or ideas about the causes of “sexual stance” among homosexuals? Most homosexuals seem to have a tendency to be either “active” (giving) or “passive” (receiving). (Though, there are also many that are flexible.)
    What could be the cause of these preferences?

    I mean, what would be a pathogen’s incentive to create these preferences? Causing “active” promiscuity is obviously logical, to maximize distribution of the pathogen.. But why on earth would a pathogen influence its host with a “passive”, receiving preference?

    Also.. Why would a pathogen limit the host to a specific sexual preference at all? If anything, you’d assume a pathogen that wants to be distributed, would make the host pansexual, or atleast bisexual?

    If a pathogen is the exclusive cause of homosexuality.. How does it even spread? Since all participants of homosexual intercourse would already have the pathogen, evident by the fact that they’re engaging in that behaviour.
    Is rape the only means of transmission? There aren’t nearly enough incidents of homosexual rape to explain the number of homosexuals.

    Another explanation could be that it could initially be transmitted through heterosexual sex. But that would either “convert” the new host exclusively to homosexuality, which sounds very unlikely, given many homosexuals are “born gay”, and have never engaged in heterosexual intercourse.

    Or it would make the new host bisexual, which fails to explain the cause of exclusive homosexuality, and especially; exclusive homosexuality with an exclusively “passive”, receiving preference.

    Though, an explanation that could explain how some people are “born gay”, could be fetal transmission from an infected mother. But this still doesn’t explain exclusive homosexuality, or passive preference.

  113. prefer to remain anonymous says:

    Old thread but I hope the webmaster, at least, sees this….

    1) Sigmund Freud reported that homosexuality was “phenomenally rare” among Orthodox Jews.

    2) This surely isn’t genetic, as there are many, many gay secular Jews. It must be something about the Orthodox lifestyle.

    3) It’s probable that homosexuality (or at least male homosexuality) is caused by some as yet unidentified pathogen or parasite.

    4) Many of the obscure biblical laws the Orthodox follow, are now known to be associated with infection control. A few random examples include —
    a. a vessel contaminated by a lizard (salmonella) or a mouse (hantavirus) cannot be used for food.
    b. a captive woman had to have her head shaved (head lice), her nails trimmed (lice eggs aka nits), and her old clothes discarded (body lice), before you could marry her.
    c. tattooing is forbidden (strongest statistical risk factor for hepatitis C)
    etc. etc. etc. Indeed the biblical promise is, follow the law, and you will not be afflicted with the diseases of the Egyptians! Infection control 3000 years ahead of its time.
    and therefore..

    5) Hypothesis — Something about the Orthodox Jewish lifestyle, blocks the transmission of the homosexuality-inducing microbe. We can narrow down the search for the microbe simply by looking at the kosher laws and what microbes they inhibit.

    Please, please don’t let it be bacon……

  114. j3morecharacters says:

    I am sorry to have to inform you that Freud, as in many other things, is wrong. Orthodox Jews are as homosexual as the rest. Sure, they marry young and have children, and many family tragedies. You seem to be unfamiliar with Orthodox Jews:

    b. a captive woman had to have her head shaved (head lice), her nails trimmed (lice eggs aka nits), and her old clothes discarded (body lice), before you could marry her.

    They dont capture women nor marry them, at least in the last 3000 years.

  115. anonymous says:

    “…99% of narcolepsy cases happen in the 25% of the population that has a particular HLA type – which suggests that something, probably a virus, triggers an overenthusiastic immune response that zaps a neuron subpopulation… compare narcolepsy to type I diabetes or Parkinson’s disease. Suppose there’s a neuron subpopulation that performs a key function in male sexual desire…”

    Why not do a study of HLA antigen markers verse obligate male homosexuality? That might be the answer right there. If most or all OMHs have one specific HLA type, then it will be easier to zero in on the cause.

    • tl says:

      After over two decades of HIV/AIDS research, wouldn’t someone have noticed if gay men have the same HLA type?

      Speaking of which… the Malaysian plane shot down evidently carried many of the top resaerchers in HIV, headed to Australia for a conference. I suppose there will now be harried calls for the “brightest of minds” to take their place and money thrown at them to lure them.

    • Dale says:

      More to the point, if the HLA distribution of male homosexuals was unusual relative to the societies they’re in, it would be a string sign that an autoimmue process was involved. (See for example the Wikipedia page “HLA DR”.) Even if researchers aren’t explicitly looking for it, a GWAS should show if there was HLA correlation.

  116. genemachine says:

    Authors retract paper “confirming” that narcolepsy is an autoimmune disease:

    Authors retract paper “confirming” that narcolepsy is an autoimmune disease

    The retracted paper is “CD4+ T Cell Autoimmunity to Hypocretin/Orexin and Cross-Reactivity to a 2009 H1N1 Influenza A Epitope in Narcolepsy”, De la Herrán-Arita et al., 2013

  117. Gridlock says:

    Simple answer. If Homosexuality is contagious, then you should not be looking for ONE PATHOGEN, but dozens.

    Think of Homosexuality as a Door Opener function of transmission.
    Turn a man into a horny gay man (increasing disease vector transmission) and that opens your pathogenic transmission routes to the urethral tract, the bowels, and the oral regions.
    It isn’t so much as a infection end-goal, but a way to increase transmission vectors.

    It could easily be a simple non-lethal reproduction strategy for viruses or parasites or other pathogens. Let us take Polio as an example. If Polio adapted a “Turn men gay” strategy, then it now has infection routes directly into other men. But you say, “Why preach to the choir?” or “Why infect the already-infected? SEX. HETEROSEXUAL SEX. VIRAL HETEROSEXUAL-SEX.

    Most pathogens reproduce ASEXUALLY making clones of themselves. The problem. The hosts can adapt and shut the parasite or virus out with a tactical mass-inoculation response.

    What do antibiotics and anti-parasitic drugs and inoculations have in common? Correct, they target one version of the infectious organism, the ASEXUAL CLONES. So what does HETEROSEXUAL SEX gain infectious organisms by turning men gay? The ability to do a little horizontal gene-transfer between different human hosts (like having a big reunion party in the bowels). Successful genetic survival strategies are shared while the “human spaceships” are “docked” and these pathogens are gaining the net benefits of HETEROSEXUAL SEX and abandoning ASEXUAL CLONING STRATEGY by turning men gay. The more pathogen types that can turn men gay (while the pathogens practice heterosexual reproduction), the more infection vectors to obtain more “human spaceships” will be gained.

    Why should a single parasite or virus or bacteria not take advantage of a change in tactics? Expect hundreds of them to “turn men gay” because the clever antivirals, inoculations, and antibiotics are changing the rules on “Survival of the Fittest” to declare that HETEROSEXUAL SEX wins for the microscopic invaders by making HOMOSEXUAL SEX a viable transmission vector route for infection & HETEROSEXUAL reproduction strategy in parasites or viruses or bacteria colonies.

  118. Gridlock says:

    Of course, there are other theories.
    One simple one is PROXIMITY DENSITY REACTION (a form of genetic birth control).
    Think mushrooms. Fungus begins as microscopic individual colonies, but at a certain population density, it grows into a mushroom and spores off a new colony a distance away from itself.

    Now for humans, we have limited local resources to draw upon in many world locations.
    Now if the population density gets too thick, causing proximity stress, there are many ways to handle this issue by genetic impulses before everyone starves:

    (1) Drive out the excess population to another location (colony sporing like mushrooms).
    (2) Proximity Territorial Rage (think of Beta Fish, two in a bowl and one kills the other)
    (3) Cannibalism (island populations on a small landmass primarily once the food supply runs low)
    (4) Wicked Stepmother (kill the babies of your competing neighbors so your babies can thrive, that’s how the lioness sleeps tonight)
    (5) Homosexuality (switch gender attractions to same-gender mates, no new babies from two male genelines or two female genelines, less male-male competition, more room)
    (6) Ritual Human Sacrifice (into the volcano you go, or we eat your heart out, or the kids get stabbed on a rock)
    (7) Paranoid Fleeing Instincts (wandering Jews who instinctively are paranoid, but also instinctively cause problems so as to induce the native population to chase them away).
    (8) Law & Terror (if no “Lethal Executions” for crime, the kinder & prolonged, jail rape version of “Ritual Human Sacrifice”, in which imprisoning the genetically-psychopathic reduces the reproductive opportunities of the Anti-Human serial-killer types while they are imprisoned)
    (9) Serial-Killing (treat your fellow human populations as a target food group or as an acceptable killing target).

    Note that #1, #7, #8, and #9 can all cause human populations to flee a land zone in a non-lethal manner (passing those genes to wider geographical zones and allowing more Earth landmass to be converted into human controlled habitable zones).

    The rest tend to act as active “EUGENIC EVENTS” which cull the weak from the strong of the herd.
    #8 — If used to eliminate the genetically-psychopathic from the population will result in strong herd-stability and a self-domestication of the population. #8 practiced with mere imprisonment (no kill policy) for violent prisoners results in a steady increase in local violence and usually the extinction of the local tribal zone.

    #5 — Is great for networking & communication of one human population tribe with another. Unfortunately is also is a great pathogen transmission route which can rapidly afflict then extinct the local tribal populations.

    #2, #3, #4. #6, and #9 — Are great for island populations with a very limited resource (fresh water usually) which cannot be divided into smaller chunks. However, when the populations that practice these genetic drives spread to non-island zones, their actions lead to the non-insane populations killing all the members with those genetic drives as quickly as possible.

    #7 — Is a workable genetic survival tactic, until larger numbers of humans outside of your tribe recognize you as operating with the genetic survival tactic #7, then they chase you off. If the #7 group also has large numbers of their members practicing genetic tactics #3, #4, #5, and #9 then they kill you systematically without even regretting it.

  119. Thagomizer says:

    John Derbyshire article from 2005 is still the best collection of theories on the topic I’ve found: http://johnderbyshire.com/Opinions/HumanSciences/metaphysicssciencehomosex.html

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  123. What do you make of the recent progress in artificial intelligence such that algorithms are able to deduce a person’s sexual preference w 90%+ accuracy using facial photographs?

    • gcochran9 says:

      Not too much, since it’s making use of everything, every visible trait, many of which are fashion, rather than biological characteristics. Let me give an example: it is as if I could recognize a woman at a distance by her wearing a dress, rather than wide hips. The dress might be a purely social thing, not really tied to her biological nature.

      Now if the algorithm worked on people wearing the same clothes, no makeup, no jewelry, same age, similar expressions – then maybe it would be telling us something.

      • The algorithms are not makinguse of “everything visible” and are taking zero note on fashion (clothing). From the study: “Facial features employed by the classifier included both fixed (e.g., nose shape) and transient facial features (e.g., grooming style). Consistent with the prenatal hormone theory of sexual orientation, gay men and women tended to have gender-atypical facial morphology, expression, and grooming styles.” — https://osf.io/fk3xr/

      • A note from the study: “The results show that the shape of individual facial elements enabled high classification accuracy for both genders. A notably high accuracy was provided by facial contour alone (red landmarksinFigure 1): 75% for men and 63% for women. This provides additional support for the link between jaw shape between gay and heterosexual faces observed in Study 1c (seeFigure 4). While the outline of theeyes, eyebrows, and mouth is—to some extent—affected by facial expression and grooming, facial contour is relatively inflexible, emphasizing the predictive power of fixed morphological traits.”

        • Ethan says:

          Buck, you are right – Ewald has said that perhaps the pathogen triggers a hormonal response in utero. Although, maybe facial differences are linked to a specific sub-population of gays.

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  130. Samanto Hermes says:

    There’s a theory that says that the same factors that cause higher IQ are the same that suppress species’ innate characteristics, i.e. causing autism, homosexuality, creative genius, etc.: https://archive.is/BsxMm

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