I think it probably has to do with the roles women play in our society. We might say that everyone is equal, but the traditional roles are still very present even today and it's a new attitude that is pretty unique for the "western" society as well. When you get right back down to it, we still expect the girls to be nice and the boys to be "boys" and rough it up. And as much as we all like to be individuals, we still end up behaving to how we are expected to behave - with exceptions of course. This probably reflects in those statistics as well.

That being said? I don't think these people have ever been to fandomhigh, because most girls around here can beat the crap out of me any guy.