This thing is not genetic dude, for God's sake. Why don't you people understand it's simply because of the way our society is! A woman here is not rewarded to be independent, make their own career, even if woman manage to do so, they won't have a good male partner (and to society, the father of the kid, or, at least any other man, and man only, should be your spouse/partner) supporting her, taking care of her kids. To be brutally honest, a woman, in general, can't get support from a man in any other way than his money. I'm seeing this in my life dude, oh, how I wanted a househusband, but that thing is impossible given our society. So, most women, given a choice to choose their own partners, given the context of our society, will marry up. It got nothing to do with genetics.