A new study came out from Mathematica, commissioned by the Department of Health and Human Services, testing the effects of sexual abstinence education courses aimed at middle schoolers. As previous studies have shown, abstinence-only curricula don't have an effect. One new element in this study: unlike previous studies, taking a "true love waits" pledge or the like had no effect, either.
Most of these programs in this study were targeted at high-risk populations, so the overall results are not representative of all kids. It is good news, therefore, that even in this high-risk population, half were still virgins late in high school.
One section of the study profiled the kids who were abstinent. Of the many factors that the original curricula included, such as improving knowledge of which contraceptives worked best, and what the risks of sexually transmitted diseases were, none made any difference in whether kids would actually avoid sex as teens. Only two factors were significant predictors of teen abstinence:
1) If the middle schoolers supported abstinence themselves; and
2) If their friends did, too.
This study could not take the question back one step further: why do some middle schoolers believe in abstinence, and why do they find friends who agree? I think the heart of the answer to that question is that those kids are more likely to have parents who clearly support waiting for sex, make a credible example in their own lives, protect the kids from some temptations, and know who their kids' friends are.
There is no magic bullet to assure teen abstinence, but there is much to give us hope – most especially, the fact that most kids are smart.