Via Bree and BunnyFactor10, we find this BBC article. Apparently young Americans who pledge to remain virgins until they marry have the same rates of sexually transmitted diseases as those who do not:
But they are much less likely to use condoms, the research found. “It’s difficult to simultaneously prepare for sex and say you’re not going to have sex,” the study’s author Peter Bearman told the AP news agency.
The pledgers are actually probably having considerably less sex, but they’re also using considerably less birth control. Disappointingly, it’s a false conclusion to draw that your conservative virgins are getting as much tail as your average kid raised by hippies.
DarrenBarefoot.com 
Their definition of sex is likely limited, too. Someone should tell them that you can get and spread STIs (sexually transmitted infections…the new(er) jargon) from acts other than intercourse.
I read a study that I can’t find anymore that was showing signifigant increases in STDs among students taught an abstinence only sex-ed program.