Jennifer Roback Morse’s views on sex and marriage are worth reading if you are interested in what happens when natural law theory, evolutionary psychology and conservative family values are stewed together and left to simmer in a base of visceral disgust toward homosexuals. I leave it to legal scholars to explain what’s wrong with arguments from “what nature intended.” Feminists can take Morse’s complaint that “we have already redefined the social context of marriage in the name of equality for women” and invite her to pine for the days before the Married Women’s Property Act. And the political theorists amongst us can discuss how Morse manages to get from the premise “Sexual activity and childrearing take place inside the private spaces of the home, far outside the reach of the public-enforcement power of the state,” to the conclusion that it’s “utterly reasonable” for the law to ban homosexual unions.

I confine myself to a sociological observation. Morse claims that a central feature of heterosexual sex within marriage is that it is “an engine of sociability that calls us out of our self-centeredness.” If anything, the opposite seems to be the case. A long-standing idea in sociology is that as you meet someone and later marry and have children, your social network will tend to get smaller. It’s called dyadic withdrawal. The married couple looks within itself for its sociability. Your spouse is usually around and you already have their phone number. Beyond that, kids keep you pretty busy. Recent research confirms the basic tendency. So, natural or not, I wouldn’t rely on the idea that sex within marriage “builds up community, starting with the spousal relationship and adding on from there.”