In her NYTimes blog Judith Warner argues that adults want to believe in teen promiscuity (and other forms of "moral panic") because it masks more complex problems. This is familiar territory, think of the alarms raised over the "Overscheduled Child," the "boys are falling behind girls in school" phenomenon, or the "Overmedicated Child."
After all, moral panics – particularly those concerning children – always serve some hidden purpose. “Modern ideas about the innocent child have long been projections of adult needs and frustrations,” Gary Cross, a professor of modern history at Penn State University, writes in his 2004 book, “The Cute and the Cool: Wondrous Innocence and Modern American Children’s Culture.” “In the final analysis, modern innocence has let adults evade the consequences of their own contradictory lives.”
All the examples of child myth-making that I’ve mentioned here have to do, at base, with the perceived corruption of childhood, the loss of some kind of “natural” innocence. When they depart from kernels of reality to rise to the level of myth, they are, I believe, largely projections that enable adults to evade things. Specifically, the overblown focus on messed-up kids affords parents the possibility of avoiding looking inward and taking responsibility for the highly complex problems of everyday life. (source)
The fact is that the best way to delay the onset of sexual activity in children is to be engaged in good solid parenting. "Teenagers with more parental supervision, who come from two-parent households and who are doing well in school are more likely to delay sex until their late teens or beyond. 'For teens, sex requires time and lack of supervision,' Dr. Kefalas said. 'What’s really important for us to pay attention to, as researchers and as parents, are the characteristics of the kids who become pregnant and those who get sexually transmitted diseases'" (source). Usually, it is argued, kids who engage in risky behaviour (sexual or otherwise) are acting out because of underlying problems such as low self-esteem, isolation/loneliness, and poor emotional intimacy with parents. Blaming traditional sex education as being too permissive or popular culture is not a sufficient response to the very real problems that some kids have.