>I disagree about the biological part - (see my reply to Nix above, along with a definition for gender) and the psychological can be explained as learned behaviour too.
Not in all cases. At least incidences of homosexual behavior in _animals_ are pretty constant throughout all populations. In human societies they are fairly stable as well.
>Regarding the 'very real gender differences in gender-related behavior that start before the age of 3', I would want to look very carefully indeed at these studies if they are trying to demonstrate that the behaviour arises from a biologically-determined origin.
However, brain is very malleable especially regarding high-level abstract thought. So there's no real significant difference in the _ability_ of women to be good at math/science.
I think what _might_ be somewhat biologically driven is inclination of women to study hard science/math. And since we're talking about inclination, and not ability, it can be effectively influenced by social environment.