@boomerang,
Well, I loved "boy" and "girl" things....and so did my male friends when we were little.
I loved construction toys and trucks and stuff...and cowboys and Indians, and also dolls and stuff.
The boys loved my girly stuff, too...but knew better than to play with it when adults were around.
I stopped at the footbrawl stage, though....I hated (and still hate) the aggression and physical mayhem. I also hated the male putdowns about sexuality, and still do.
So, damned if I know.
I think there is a continuum with clusters of more girls than boys at one end, and more girls at the other.
If it's all so innate, though, I wonder why so many cultures expend such crazy energy in trying to enforce gender roles?
Think of the way in which boys who express less traditional masculinity have been tortured through the ages, and how women were kept in what was assumed to be their natural place by quite brutal laws and social censure?