Why did the Nobel sperm bank produce only a couple of hundred kids? And why are so many of the mothers from the bank who contact me divorced? Here is one tentative theory: The people most likely to use a Nobel sperm bank are people who really believe in genes. They expect the high-quality sperm to give them high-quality children. If they didn't believe it, they would be satisfied with run-of-the-mill semen. They prize nature over nurture.

But how does a man who believes in genes feel about a child who does not share his genes? If you believe that genes rule a child, then you might not feel like a father to a child that is genetically not your own. In other words, the men most likely to believe in the principle of the Nobel sperm bank are the very men who would be most alienated by a child from the sperm bank. I suspect that problem alienated men from being clients: Because they believed in it, they could not bear to do it.

For the same reason, it may also be no accident that almost all the parents who have contacted me about their Nobel sperm bank kids are divorced mothers whose ex-husbands have terrible relationships with their kids.