Bostonian - I was going to make the same point about the wider societal differences.
http://www.nytimes.com/2005/09/20/national/20women.html?pagewanted=printI don't think this is a problem that is specific to Princeton. It's still a male-dominated world in many arenas, and co-ed colleges are no exception. Not only are roles such as leadership positions different for men and women in college, but career ambitions for men and women differ. More women are expecting to leave their careers for child-rearing responsibilities. This trend was reported in the New York Times study in 2005.
I work in a male-dominated profession. I don't think that will change in my lifetime. Women in my profession make less money, on average, and don't achieve the prominent positions in the profession. I'm not surprised the eating clubs at Princeton don't have many women in power - neither do the presidents of academies in my profession, either.
Maybe the trends reported in these studies are a result of those of us now in the trenches, who thought we could achieve professional equality, and who have told our daughters to be a little less ambitious. I certainly have.