I am a sociologist. In the great argument about whether sex roles are more nature or nurture, sociologists are pretty much obliged to believe that gender differences are 1% nature and 99% nurture. It’s practically a union regulation. Part of the reason we believe that sex roles are socially constructed is from scientific evidence. But another part of the reason we believe this is because it gives sociologists more power. If sex roles – and, indeed, all of social life – can be reconstructed, who better to do it than sociologists?
Two things changed my mind. First, I got married and had kids, a boy and girls. My wife and I graduated from the West Point of political correctness. We tried to raise our kids androgynously. It didn’t work. Nature will out, and it did. They are not sexists, but the girls are clearly girls, and the boy is clearly a boy. And in the process of being pregnant and having little babies and getting more and more married, my wife and I discovered that we are female and male in deep and ineluctable ways. Which is fine.
The other thing that changed my mind was studying sociobiology. Sociobiology, also known as evolutionary psychology, argues that many of the regular features of human behavior are deep in the human nature because they conferred an evolutionary advantage, long ago if not still today. The key idea of sociobiology that affects family life is that in mate selection, women do the choosing. This is Darwin's theory of "sexual selection," which accounts for competition among individuals within a species in the same way that his more famous "natural selection" accounts for competition among different species. Women do the choosing in mate selection because they bear much more of the risk from mating.
The basic idea is that women have a long list of what they look for in a husband, with resources and commitment being the two basic categories. Men, on the other hand, have a pretty short list: youth and beauty in any woman; youth, beauty, and fidelity in a wife. (Homosexuals, by the way, use pretty much the same rules.) And at root, mate selection is not about the married couple, but about their children. This fundamental asymmetry in what the sexes want means that courtship is a dance, a back and forth of displaying the necessary attributes for making and raising children well, and committing those necessary attributes for keeps. Men and women are almost like different species in their approach to having children – make many and hope some survive vs. make a few and nurture them carefully.
Marriage is a great cultural achievement that unites these two strategies. All cultures have invented some form of it, because our mammalian biology is at is starkest when we are dealing with the difficulty of caring for infants. There are only a few social strategies that really work, though individual variation in any society is enormous around those basic models.
So where does this leave me on nature vs. nurture? I am trying to hold the line at 50/50.