In a recent essay in the journal Human Development, I argue that practices of friendship are the pedagogy for marriage [opens a PDF]. Single-sex dorms can likely reduce the easy, thoughtless hookup by virtue of the fact that students will not be able to stumble in a stupor into the bed of a member of the opposite sex. But "lack of opportunities for thoughtless and harmful hookups" is hardly a selling point for parents eager to see their children develop into mature adults. What is needed, in addition to single-sex dorms, are adults who model friendship and marriage; plenty of alcohol-free activities, especially at late night and on weekends; classes at 8 and 9 a.m., especially on Fridays; positive programming that allows for cultivation of different friendships, platonic and even romantic; ample conversation in classes and events about marriage and sexual fidelity; and a host of other initiatives.
Aristotle was certainly right that human beings are not only brains with bodies attached; they are shaped by practices and especially by friendships (see Nicomachean Ethics, books 8 and 9). What makes college life today so depressing for many is not just the drinking and the sex: it's the lack of real friendship. Single sex dorms are a first step to addressing the problem, by contributing to the reduction of two major obstacles. But needed still are positive steps that encourage the practices of friendship.