These days, young stars are sacrificing sex in favor of virginity vows. Momlogic explores this modern movement -- and what it means for teens everywhere.

What's the latest accessory to grace the bodies of teens wearing barely-there skirts and tummy-bearing tops? Purity rings. Selena Gomez, the 15-year-old star of Wizards of Waverly Place, wears one on her left ring finger that says: "True Love Waits." And the pop group the Jonas Brothers (Kevin, 20, Joe, 18, and Nick, 15) don silver metal bands to signify their promise to God to remain virgins until marriage.

American Idol winner Jordin Sparks says of her ring: "My parents gave me a purity ring and talked to me about waiting until I'm married to have sex. It wasn't forced; it just made perfect sense. It's going to be awesome to say to my husband that I waited my whole life for him."

These stars seem to want to prove they can be young and have fun without sacrificing their beliefs. And although this celebrity pledge may inspire young teens to wait until marriage, the numbers show they are just a reflection of a booming trend. Over the past decade, the number of Web sites selling purity rings has skyrocketed. In fact, sociologists found more than one in eight American teens have made a virginity vow to God.

K-Mart now sells gray, yellow, and blue sweatpants that proclaim in what they call "bold abstinence screen print" a logo that reads "True Love Waits" on the crotch and butt of the pants. And there's a new magazine geared toward junior high and high school students called Just For Girls, which encourages "abstinence living."

The good news: Studies have shown that purity pledges lower the risk of early sexual activity and teen pregnancy. The bad news: Researchers have also found that girls who make purity pledges were six times as likely to engage in oral sex than virgins who hadn't taken a pledge, and were also less likely to use a condom the first time they go all the way.

What do you think of purity pledges: good idea or a waste of time?