Well, first of all, we're all a vast mix of male and female, all of us. But, on average, men have a great deal more testosterone and women have a great deal more estrogen. And there are just hundreds of studies now that show that these have an impact. Now, culture has an impact, also. Bu in fact, if you inject a fish or a lizard or a monkey with testosterone, it begins to fight for rank.
Men are much more interested in rank than women are.
Women are more interested in balancing work and family, and that seems to be estrogen-related. So men's spatial skills are directly related to testosterone. And, indeed, some 90 percent of architects are men, some 80 percent of engineers and mathematicians are men. I'm not surprised. But what's interesting is we're finally in a time in human evolution where those women who want to go into math or engineering or architecture can do it.