The Innocence Project

He compares the situation to that of a Swedish town that simultaneously had a lot of storks and babies. "They decided storks bring babies," Bearman says. "Actually, though, storks breed in chimneys. So when there's an increase in population—i.e., babies—there's an increase in houses, chimneys, and thus storks. Babies and storks are independent things that occur in this particular town simultaneously—like virginity and good grades in a certain kind of person."

In addition, Bearman discounts the influence of virginity pledges on those declines in teen pregnancy and abortions. He explains that pledges succeed at delaying sex only within an extremely narrow set of circumstances: if an adolescent is between 14 and 16, and if she's part of a group that consists of no more than 30 percent of the population where she's growing up. "The only way the pledges work is if they draw kids into a moral community and give them a sense of identity," Bearman says. Under these circumstances, teens delayed having their first sexual experience by an average of 18 months.

The problem, Bearman says, is that 88 percent of pledgers wind up breaking their promise. "And you can't take a purity pledge and carry a condom in your pocket," he says. "From what we can tell, pledgers have fewer partners than nonpledgers and they are sexually active for a shorter period of time; however, their STD rates are statistically the same as nonpledgers. Pledgers are much more likely than nonpledgers to engage in substitutional sex—including acts that may put them at higher risk for STDs, such as oral and anal sex. "

It's interesting to note that at the same time that abstinence programs were on the rise, another statistic shifted—one that many experts believe had a larger impact on teen pregnancy and abortion rates. Planned Parenthood Federation of America president Cecile Richards points to the increased use of condoms by teenagers, from 46 percent of sexually active high school students in 1991 to 63 percent in 2005. In fact researchers at the National Campaign to Prevent Teen Pregnancy have found that some of the most effective programs to get teens to put off having sex offer them information on both abstinence and contraception, or sex education in combination with activities that don't have anything to do with sex—sports, arts, or mentoring.

Teen pregnancy, STDs, and public policy were not on Randy and Lisa Wilson's minds when they held the first Father-Daughter Purity Ball in Colorado Springs nine years ago. They love creating rituals that bring families together, particularly ones that give fathers ways to be involved in their children's lives.

Their passion is born of personal pain. When Lisa was 2 years old, her dad walked out on her family. Although he later tried to establish a relationship, she says, "I felt as if my father ripped my heart out and threw it on the ground and said, 'Deal with it.'"

Randy says his dad "unintentionally abandoned" him. "He was a great provider, but we didn't do relationship well. Dad worked nights, so he wasn't there for my football games or basketball games. He never saw any of that, so he never saw me."

Randy, now Family Life Pastor at Colorado Springs' Mountain Springs Church, has done a lot of research on the importance of fathers in their daughters' lives. It's true that studies have shown that girls with involved fathers get better grades, are less likely to use drugs, and have better self-esteem than those whose fathers are uninvolved or absent.