ALMOST EVERYONE AGREES teenagers need education about human sexuality and the consequences of being sexually active. And little disagreement exists that such information should go beyond the basic facts of anatomy and biology, that is, the names and functions of the various reproductive organs. Teaching the basic facts of sexuality, a recent editorial in Glamour states, simply is not enough. "The facts increase knowledge but more intensive intervention [into teenagers' lives] is required to affect sexual behavior, experts have found. What does affect behavior is practical information. . . . And when you teach a teenager, you're also teaching the adult he or she will soon become." In an age when more than a million teenage girls become pregnant each year, few people—liberal or conservative on the issue—can find fault with the basic premise of...