I think a debate is needed between Hanna Rosin (who claims that the “hookup culture” is empowering women) and Kay S. Hymowitz (who pointed out that the “hookup culture” is most prominent among women who aren't exactly empowered).
I think there's a lack of control groups. Ms. Rosin looked at women who “hooked up” and appeared to be getting ahead. As far as I know, she didn't look at females who didn't get to college in the first place (who are even less likely to marry and are more likely to abort or give birth out of wedlock) or the dissenting virgins (who might also be getting ahead). The closest approximation to a control group were those women who had boyfriends back home (who might have started “hooking up” even earlier).
I won't more than mention the sample size of 53.