Intelligence is highly heritable- so generally, when someone is far smarter than average, his parents are at least somewhat above average.
But Gauss’s parents sure looked ordinary: his father had menial jobs such as gardener and street butcher, while his mother was barely literate. Nonpaternity is not very common, but it is more likely if a kid is vastly different from his parents: and Gauss (arguably the greatest mathematician of all time) was vastly different. Perhaps the most different kid in history.
So if we dug him up and sequenced him, we might discover something interesting. In the immortal words of Zuckerberg: “He’s not your dad.” Maybe.
Generalizing this case has obvious implications.