It's all about sex

Modern science is all for evolution except when it comes to human behavior. They prefer to believe — and belief would seem to be the proper word — that differences between how men and women act are in every case a result of socialization. Raise children differently, they argue, and they will behave differently.

The 2007 book Why Beautiful People Have More Daughters by Alan S. Miller and Satoshi Kanazawa challenges that idea. The book was actually written by Kanazawa based on ideas formed by Miller, who died early in the project. Kanazawa generously listed Miller's name first.

The book, as the title suggests, uses a question and answer format. Why do men like blonde bombshells (and why do women want to look like them)? Why does having sons reduce the likelihood of divorce? Why are diamonds a girl's best friend? Why might handsome men make bad husbands? Why are almost all violent criminals men? Why do some men beat up their wives and girlfriends? Why is sexual harassment so persistent? Why are women more religious than men? And, of course, why do beautiful people have more daughters?

People in all cultures behave essentially the same, the book tells us. Studies that suggest that certain cultures are radically different are in each case either mistaken or fraudulent, as in the case of Margaret Mead's celebrated book on Samoa. So the answer to every question comes down to differing male and female reproductive strategies. Men can theoretically have hundreds of children; women can have relatively few. Women always know who their children are; men can never be certain (or at least not until recently). This explains almost everything, the authors say, although some explanations get a bit convoluted.

There are a few questions evolutionary psychology cannot yet explain, and Kanazawa frankly admits this in a final chapter? How do you explain homosexuality? Why do parents in advanced societies have fewer children? And a few others. To pose one more question, why must one theory explain everything?