NORTH ANDOVER — Three-hundred teenagers crammed into the Rogers Center at Merrimack College last night yelling out, "Sex is great."

But not until marriage, that is.

In a time when racy teen television shows have flooded the airwaves and celebrity teen pregnancies are dominating magazine covers, local high school students slid silver rings on their left ring fingers and vowed to practice abstinence until they hear the wedding bells.

Sixteen-year-old Andy Saulnier was there for a second time, back for a replacement after losing his first abstinence ring he received four years ago.

"You think the media would tell you not to have sex," the Amesbury teenager said. "They say it's OK to do it. ... I'm fine wearing my ring. When I first had it I got picked on a little, but I don't care. More people have them now."

The vow was part of a presentation by the Silver Ring Thing, a national faith-based abstinence program that uses an MTV-like approach in getting their message across. There were flashing lights, rap music and comedy sketches with references to pop culture giants like Guitar Hero, Harry Potter and Apple.

Andover band One Step Away opened the show.

"They give the right approach to it," Kristina Rex, 15, of Andover said, showing off her ring. "They're not shoving it down our throats, saying sex is awful."

This was the Silver Ring Thing's 10th performance in the state since 2002. St. Augustine Youth Ministry in Andover sponsored this event.

Missy Patton, a Silver Ring Thing road manager, said more than 100,000 teenagers around the world are wearing their rings now.

"It definitely is growing," Patton said. "In the hearts of teenagers there is a desire for the message. You don't have to follow what the media is telling you. Virginity isn't a bad thing."

The silver rings — also called promise rings — bear inscriptions like "True Love Waits" or "One Life, One Love" and are worn by both sexes. Silver Ring Thing bands are inscribed with "Thes 4:3-4," which is a Bible verse about keeping clean of sexual sin.

They've become the new must-have accessory among a growing group of young celebrities at the same time that teen pregnancies like Jamie Lynn Spears' (sister of Brittney Spears) and Bristol Palin's (daughter of vice presidential candidate Sarah Palin) have dominated the headlines.

Disney stars like Miley Cyrus, The Jonas Brothers, Demi Lovato and Selena Gomez all sport the rings. American Idol winner Jordin Sparks also wears one.

The rings garnered a barrage of media attention last month when British comedian Russell Brand made fun of the Jonas Brothers' chastity pledge during the MTV music video awards.

"Our founder went on the Today Show. ... We got some phone calls after that," Patton said. "We'd like to let celebrities like the Jonas Brothers know we support them."

While the teenagers watch skits, parents are brought to another room where they receive abstinence talking points.

"We don't allow a man or woman who finishes medical school or law school to act as a doctor or lawyer until they have their license," said the Rev. Bill Waters, a campus minister at Merrimack, explaining what he tells parents. "Many think people can act as if they're married even if they haven't said their vows."

But does it get through to the teenagers?

Some of the teenagers at last night's event said they were there as a requirement for their confirmation classes or at the urging of a parent, and said they weren't sure how seriously they would take their rings — if they wore them at all.

A state Youth Risk Behavior Study released this year by the Department of Public Health showed that 44 percent of the high school students surveyed had had sex. Twelve percent had sex with multiple partners.

Studies are conflicted over whether abstinence vows keep teens from having sex.

But some attendees appeared to have left serious about the message.

"They said a lot of things you should really think about," Monica Polanco, 14, of Lawrence said. "When I came in I thought this was just about some ring. But there's this message."

The rings cost $20, a small price to pay for some abstinence believers.

"And there's no refund for your virginity," Silver Ring Thing speaker Neville "Paco" Pancham told the crowd. "The world tells us you can't date and wait. That you can have sex without consequences. ... We're not buying into that. We're making some history tonight."