Unlike you, an evolutionary biologist knows that if enough of his siblings and cousins have children, the probability is very high that most of his genes have b

Unlike you, an evolutionary biologist knows that if enough of his siblings and cousins have children, the probability is very high that most of his genes have been passed on even if he wasn't the one to do it. Also, only 50% of your own get passed on per child, so it's entirely possible more of your genes were passed on by other people even if you have a child or two.