Nah ... I don't believe in the "nature" argument on this issue. I'm thinking of how girls' math abilities seem to magically dwindle when they hit their teens, and how that coincides with the boys in their class hitting their teens and starting to assert their presumed "dominance" over certain fields of life seen as predominantly "masculine". A colleague of mine here was studying kids that age and how they used spaces around their neighborhoods. Girls who wanted to do snowboarding had found that they had to be on the slopes right after school for an hour or so before the boys got there. As soon as the boys got there, they mercilessly teased the girls away. A couple other colleagues studied women engineering students (hey, we're a technical university after all, and the uni has from time to time tried to do something about equal recruitment and student retention). Same thing there. It wasn't that these women weren't interested in engineering; it wasn't that they couldn't handle the math; but, men students and teachers alike consistently broke down the women's self-confidence by laughing at their mistakes, ignoring their insights, and generally making them publicly visible only as sexual objects rather than as colleagues. For instance, when a woman student contributed a brilliant observation or question ... silence. Then some male student would repeat it ... and get all the credit. And this is in Norway, which in my experience is far more egalitarian than the US. For my money (a 2-cent rant's worth, but those 2 cents do come out of my wages as a professor in sociology of science), the so-called "math gap" is just another case of a prejudice reproducing itself.