What is it that explains behavioral differences between the sexes? Is it primarily a sexist culture, as gender theorists maintain? Or is it primarily the powerful effects of testosterone?
Carol Hooven is well qualified to provide an answer. She has a PhD from Harvard in biological anthropology, and she teaches at her alma mater. Her book examines the scientific evidence in detail. The bulk of that evidence suggests that while socialization has an influence on behavioral differences, the main cause does not stem from how little boys and girls are raised.
There’s an understandable concern that innate differences can be cited to reinforce patriarchy. Consequently, some would downplay or deny those differences. In citing biology, Hooven does not seek to defend or justify male violence. Nor does she support sex discrimination and patriarchy. She does favor recognizing what science tells us – instead of downplaying or denying it in the name of equality, as authors such as Angela Saini and Cordelia Fine do. “Understanding the forces that drive our priorities and behavior,” Hooven writes, “and how genes, hormones, and environment interact, helps to equip us to combat the darker parts of our nature.”
The basic facts are these:
• Men have ten to twenty times as much T as women.
• T’s main job “is to support the anatomy, physiology, and behavior that increases a male’s reproductive output.”
• “We are born into a gendered social environment, with different expectations for the sexes.” Nonetheless, “boys’ and girls’ brains are not gender-neutral blank slates.”
• In lab animals, fetal exposure to high T prevents the capacity for normal female sexual behavior.
• Differences in how young rats play are similar to those between boys and girls.
Does it make sense that human beings are the exception in the animal kingdom and sexual differences in how children play are unrelated to their brains? Hooven contends that prenatal T exposure significantly accounts for different play styles in monkeys and in humans.
Human female fetuses with CAH (a rare disorder called congenital adrenal hyperplasia) are exposed in utero to unusually high levels of T. As girls, they engage in play typical of boys more than three times as frequently as do girls without CAH. This occurs even though parents report encouraging their CAH daughters to be more feminine. Young women with CAH are also more likely to prefer male-typical professions. In sum, there is ample evidence that “exposure to high levels of T, even before we are born, masculinizes not only our bodies but also our interests, preferences, and behaviors.”
Men’s greater desire for sex without commitment is “one of the largest of all psychological sex differences in humans.” One researcher attributed this difference to “cultural influences superimposed on biological predispositions.” T levels are related to the higher libido.
Experiments with mammals also shows that male fetuses deprived of high T levels in utero have more feminized play styles as youngsters. There is no reason to assume “that humans are different from every other animal in which the relationship between T and masculinization of juvenile behavior has been observed…and that social forces alone explain why girls and boys play differently…The conclusion seems inescapable: as best we can tell, T makes boy brains.”
The evidence also suggests that T explains much of the gap between the sexes in sports. “Testosterone builds muscle, men have more of it, and it gives them a strong advantage over women in sports.” That’s why sports have been sexually segregated until recently.
One professor of gender studies claims that T levels “overlap considerably” between men and women. On the contrary, a meta-analysis of studies comparing T levels finds that adults have a “strikingly non-overlapping bimodal distribution with wide and complete separation between men and women.” The exceptions are people with DSDs or serious disorders of their endocrine glands.
Women with DSDs (disorder of sex development), whose T levels are in the high range, generally outperform women within the normal T range. One study found that women with these conditions are overrepresented in elite women’s sports by 140 times given their small proportion of the population. A study of female Swedish Olympians found that 37 percent had PCOS, which produces a T level up to five times higher than the average woman. Some sporting associations limit participation by women with naturally high T levels.
DSD occurs in about two of every 100,000 people. There was controversy about two women boxers in the Paris Olympics who apparently have DSD, which results in higher-than-average T levels. Neither is transexual, and both won gold medals.
T levels are also implicated in aggressive behavior, although some professors of gender studies attribute male aggression to cultural permission. Once again, Hooven looks at what the research shows. It is not controversial to say that T plays a “central role” in male violence for many non-human animals. Is it likely that humans are the exceptions here, too?
Aggression is used among animals to survive and to reproduce. Women are aggressive at times, but they tend to do less damage. One reason is they are smaller than men. Another reason is that women as well as various female mammals have higher levels of empathy, as reflected in related behaviors such as caregiving, cooperating, helping and comforting. T seems to reduce empathy. Men are more likely to use violence to prevent a mate from straying, often by attacking male interlopers. Men account for at least 80 percent of violent crimes in the U.S.
Does socialization account for this stark behavior difference? The violence gap widens at puberty, the time when T levels surge in boys. There’s no reason to believe that gender socialization suddenly surges at the same time in every culture.
When ideology conflicts with science, idealogues tend to distort or to deny the inconvenient truth. Carole Hoover gives a comprehensive, compelling, and readable summary of the research on testosterone and behavior. She gets the final word:
“It is within our power to close or widen sex differences in aggression – but the underlying tendencies producing those differences precede culture, and they exist because of testosterone. No good can come from denying that.” -30-
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