It doesn't work; in fact, it backfires:

The new analysis of data from a large federal survey found that more than half of youths became sexually active before marriage regardless of whether they had taken a "virginity pledge," but that the percentage who took precautions against pregnancy or sexually transmitted diseases was 10 points lower for pledgers than for non-pledgers.

"Taking a pledge doesn't seem to make any difference at all in any sexual behavior," said Janet E. Rosenbaum of the Johns Hopkins Bloomberg School of Public Health, whose report appears in the January issue of the journal Pediatrics. "But it does seem to make a difference in condom use and other forms of birth control that is quite striking."

Got that? The difference between teens who make abstinence "pledges" and teens who don't isn't the amount of sexual conduct, it's that those who make the "pledges" engage in more dangerous sexual conduct.

Is this news?

Not really.  The nonpartisan National Campaign to Prevent Teen and Unplanned Pregnancy found that abstinence programs do not affect teenager sexual behavior. A congressionally-mandated study, which was not only comprehensive but also included long-term follow-up, found the exact same thing. Researchers keep conducting studies, and the results are always the same.

Yet the federal government is continuing to invest in abstinence-only programs — $176 million annually.

Kevin Drum comments:

Simply telling teenagers not to have sex doesn't affect behavior, doesn't prevent unwanted pregnancies, and doesn't stop the spread of sexually-transmitted diseases. Teens who receive comprehensive lessons of sexual health, with reliable, accurate information, are more likely to engage in safer, more responsible behavior.

And yet, GOP policy makers in Washington have invested billions over the last eight years in this failed social experiment, and conservatives want taxpayers to throw even more money at programs that don't work.

The Washington Post noted that Congress and the new Obama administration "are about to reconsider the more than $176 million in annual funding for such programs." It should be a no-brainer.

Maybe with some brains in Washington now, a more rationale policy will finally see the light of day.