It has nothing to do with physiology, it's do with expectations from birth. Many studies have shown that boys and girls will play everything equally until about 4-5 years of age. After that, the kids start to try to fit in with the normal boy/girl divides..... unless their parents don't force it.
If you take a girl and don't tell her "pink is for girls, blue is for boys" then she is more likely to go in to a male oriented profession. There is a shit-ton of psychological studies showing that boy/girl pigeon holing happens due to parental influence, not physiology.