A cheerleader of the sexual revolution has second thoughts.A few weeks ago, a chirpy researcher from a London morning show asked me to appear on a TV debate about sex, along with an older, married couple who attend “swingers parties,” a teenage twit who notoriously stripped off her shirt in public in Ibiza and was rightly arrested, and Lorraine Candy, the editor of British Cosmopolitan. My role was to “even out the debate”—in other words, to be a rabidly right-wing, “no sex, please, we’re conservative” voice, and thus discredit the conservative viewpoint. But as we talked, the researcher, part of...