PHILADELPHIA -- Teens who make a one-time pledge to remain virgins until marriage catch sexually transmitted diseases about as often as those who don't pledge abstinence, according to a study of the sex lives of 12,000 adolescents.
Those who make a public pledge to delay sex also wind up having fewer sex partners and get married earlier, the research shows. But the two groups' STD rates were statistically similar.
One of the problems, researchers found, is that virginity "pledgers" are less likely to use condoms when they do have sex.
"It's difficult to simultaneously prepare for sex and say you're not going to have sex," said Peter Bearman, chairman of Columbia University's sociology department, who coauthored the study with Hannah Bruckner of Yale University.
"The message is really simple: `Just say no' may work in the short term but doesn't work in the long term."
Data from the study, presented yesterday at the National STD Prevention Conference, was taken from the National Longitudinal Study of Adolescent Health. That study was funded in part by the National Institute of Child Health and Human Development and the Centers for Disease Control and Prevention.
The analysis found that in communities where at least 20 percent of adolescents pledged to remain virgins, the combined STD rate was 8.9 percent. In communities with fewer than 7 percent pledgers, the STD rate was 5.5 percent.
"It is the combination of hidden sex and unsafe sex that creates a world where people underestimate the risk of STDs," Bearman said.
Critics of abstinence-only education saw the findings as evidence that adolescents benefit from sex education.
"It's a tragedy if we withhold from these kids information about how not to get STDs or not to get pregnant," said Dorothy Mann, executive director of the Family Planning Council, an organization dedicated to reproductive health services. But Pat Fagan, who researches family and cultural issues at the Heritage Foundation, said that one-time pledges were different from long-term abstinence education. He noted that the pledges delayed sex and led to fewer partners.
"It shows the power of the pledges by themselves," he said. "It also shows that alone, a one-time pledge is not enough. Anyone connected with the abstinence movement would never say it's enough."
The study first questioned 12- to 18-year-olds and followed up on them six years later. It found that the STD rates for whites who pledged virginity was 2.8 percent, compared with 3.5 percent for those who didn't pledge.
For blacks, it was 18.1 percent and 20.3 percent. For Hispanics, it was 6.7 percent and 8.6 percent. Bearman said the differences between those who pledged and those who did not were not statistically significant.
Donald Orr, director of adolescent medicine at Indiana University, said he hopes the study helps move sex education from a morality issue to a public health discussion.
"An environment where the only protection is not having sex creates the view that your risk for getting an STD is very low, and obviously it isn't," Orr said.