The Case for Nature
Parents sometimes worry about restricting the masculinity of their sons. They shouldn't worry. With a million years of evolution behind them, most boys will be masculine no matter what their parents do. If they are not masculine, it is more likely because of physiology than parenting. General Douglas McArthur's mother wanted to guide him so carefully that she moved to West Point to watch over him when he was a cadet. MacArthur is not the only manly hero who had an “overprotective” mother.
—Heroes, Rogues, and Lovers: Testosterone and Behavior
James M. Dabbs
© 2000 McGraw-Hill. Reprinted with permission.
Do biological factors contribute to sex differences in human behavior? Do they also lead to individual differences in masculinity and femininity? How can we answer these questions? There are a number of possibilities. First, we can examine the results of experiments that probe the impact of sex hormones on animals' nervous systems and sex-linked behavior. Second, we can study people who were exposed to unusual levels of sex hormones early in life because of genetic or hormonal abnormalities. Third, we can examine evidence on whether people's levels of sex hormones are related to gender-related behaviors, such as aggression, visual-spatial ability, and sexual orientation. And finally, we can contemplate tragic real-life events that provide information about the power of nature and nurture to influence gender—such as when a baby boy loses his penis because of a botched circumcision procedure and is subsequently raised as a girl.