Here's some empirical research on the actual causes of the pay gap. Executive Summary: The majority of the burden of child rearing still falls on women, and this can be disruptive to their careers prospects, especially in high paying fields like law and bussiness management; childless women and women who work in jobs that allow for flexible hours earn incomes much closer to parity.
Side note: I can't really tell, but some evidence suggests the total time spent on childcare has increased in the past 40-50 years. Now, when I look at people raised back then and try to adjust for the effects of leaded gasoline on the brain, they seem pretty much OK. So we should consider the possibility that we're putting pointless pressure on mothers.
A long blog post explains why the author, a feminist, is not comfortable with the rationalist community despite thinking it is "super cool and interesting". It's directed specifically at Yvain, but it's probably general enough to be of some interest here.
http://apophemi.wordpress.com/2014/01/04/why-im-not-on-the-rationalist-masterlist/
I'm not sure if I can summarize this fairly but the main thrust seems to be that we are overly willing to entertain offensive/taboo/hurtful ideas and this drives off many types of people. Here's a quote:
The author perceives a link between LW type open discourse and danger to minority groups. I'm not sure whether that's true or not. Take race. Many LWers are willing to entertain ideas about the existence and possible importance of average group differences in psychological traits. So, maybe LWers are racists. But they're racists who continually obsess over optimizing their philanthropic contributions to African charities. So, maybe not racists in a dangerous way?
An overly rosy view, perhaps, and I don't want to deny the reality of the blogger's experience. Clearly, the person is intelligent and attracted to some aspects of LW discourse while turned off by other aspects.