The day's guest instructor had spiked blond hair, tight black jeans and a propensity for street slang.

"You have been lied to, lied to by the media, lied to by celebrities," Ed Ainsworth told the 120 squirming eighth-graders at Smylie Wilson Junior High School. "Will this condom protect your heart?" he asked, flashing a glossy Trojan ad on a giant screen. "Will this condom protect your reputation? Go ahead and use a condom. You'll still be known as a slut."

This is sex education, Texas-style, where the only safe sex taught since 1995 is no sex outside marriage. That is when George W. Bush, who was then governor, signed a law making Texas the third state requiring schools to follow an abstinence-only sex education curriculum.

Now President Bush is promoting abstinence-until-marriage programs nationwide, a shift in health policy that has sparked an emotional debate over how to keep young people healthy. Abstinence-only proponents say that teaching young people about birth control is simply inviting them to have sex; advocates for comprehensive sex education say that withholding detailed information leads to dire medical consequences. Lubbock's situation illustrates the limitations of abstinence-only programs.

In the seven years since their schools began teaching abstinence-only, young people here have been anything but abstinent. Teen pregnancy rates in the state remain above the national average, and Lubbock County consistently has one of the highest rates in the state. In addition, the number of Texas youths with sexually transmitted diseases has risen steadily.

At the same time, many parents lack the time or expertise to provide adequate guidance. Teachers complain that even if the law did not limit what they could teach, the school day already is packed. And young people are living in a culture that features both regular church attendance and provocative music videos.

Now, a small group of students is revolting against the abstinence-only curriculum.

"The current policies are obviously ineffective," said Corey Nichols, 17, who, as mayor of the Lubbock Youth Commission, is leading a push for a more comprehensive program. "I think abstinence is wonderful; as a commission we back abstinence. But when you look at the numbers, you see the abstinence curriculum fails."

Risk and Routine

Lubbock is a flat, dusty farming community on the western edge of the Bible Belt, where liquor is prohibited and high school football is worshipped. Bush received his largest winning percentage in Lubbock's congressional district in the 2000 presidential election, and local lore holds that the city has more churches per capita than any other in the nation.

It would seem fertile ground for abstinence-only education.

"I really believe that's the way to go," said Cindy Wright, the mother of two girls. "The Bible says you are supposed to get married before you consummate a relationship. That may not be very popular, but I don't think teaching anything other than abstinence is right."

Since the abstinence-only curriculum began in 1995, teen pregnancy rates have fallen in Texas generally -- and Lubbock County specifically -- but not as dramatically as for the nation as a whole. Meanwhile, rates of sexually transmitted diseases have soared.

In 1996, the last year for which national figures are available, the U.S. teen pregnancy rate was 38 out of every 1,000 girls; Texas's rate was 40 per 1,000 and Lubbock County's was 43. In subsequent years, as the national and state rates inched steadily downward, Lubbock's figures fluctuated.

By 2000, the statewide teen pregnancy rate had dropped to 33 per 1,000; Lubbock County reported a rate of 42.4, said Jane Tustin, health services coordinator for the Lubbock Independent School District.

Over the last decade, as rates for gonorrhea and chlamydia have fallen nationally, Lubbock County has confronted an epidemic. In 2000, fewer than 150 cases of gonorrhea were reported nationally for every 100,000 people. Lubbock County reported double that, with the highest number of cases in people between the ages of 15 and 20.

But Lubbock has struggled with teenage sex for generations.

In 1973, the city developed a separate high school program for pregnant girls and young mothers, but it did not slow the pace of teen pregnancies. Two decades later, local officials appointed a teen pregnancy task force that met over two years, said Tustin, a task force member.

"We developed all sorts of recommendations," she said. The group urged a community-wide effort targeting high-risk behavior, such as smoking, gang membership, substance abuse and sexual activity, by providing more activities and mentors for Lubbock's young people. None of the recommendations was adopted, largely for reasons of cost.

What has persisted, Lubbock residents say, is a culture of teen sexual activity.

"We've got a lot of kids for whom the norm is to be a high school dropout and pregnant well before she is 18," said Eric Benson, who coordinates HIV programs in the Lubbock area for the Texas Department of Health. "We have instances where a girl has her first child at 15, becomes a grandmother by the time she is 30 and a great-grandmother at age 45."

Benson's observations are based partly on experience: Fifteen years ago, at age 19, he fathered a child. "I got my sex ed from three sources -- my peers, the media and my own research," he said.

Many teenagers said that with the limits on teaching, and with parents who are uncomfortable discussing sex in detail, they learn much of what they know from experience. Some young women here, under the mistaken belief that they can get pregnant through oral sex, refer to their children as "spit babies."

"I learned the hard way," said Jennifer Villarreal, 19, who gave birth two years ago. "You can continue to talk about abstinence, but kids are curious and they will experiment."

Even teenagers who have taken a virginity pledge see a community in which sexual activity -- often risky, promiscuous behavior -- is a routine part of growing up.

"Why so much sex in Lubbock?" said Shelby Knox, 16, who initiated the student effort to change the Lubbock curriculum. "There's nothing to do. You can only go to the movies so many times on Friday night."

Point of Agreement

Facing the eighth-graders at Smylie Wilson, Ainsworth asked how many knew someone age 15 or younger who was pregnant or had a child. Close to 90 percent of the hands shot up.

"Which one of you girls wants to go and have sex with a yo-yo who doesn't take care of you?" he asked. "Are you willing to trade your entire destiny for six seconds of pleasure?"

Ainsworth's make-the-adults-blush rap reflects the Bush administration's new tack on teen sexuality. He is a youth pastor, but he makes the case for abstinence not on religious grounds, but by highlighting the consequences of casual sex at a young age.

Sex outside marriage is Russian roulette, he told the students. Contracting the AIDS virus, he warned, means "a long, slow process of death" with medical care costing as much as $80,000 a year. Genital herpes "is the gift that keeps on giving," because sores on the mouth, buttocks, thigh and genitals come and go "for the rest of your life."

Joseph McIlhaney, founder of the Medical Institute for Sexual Health, said it is too early to evaluate the effectiveness of abstinence-only programs, but he has seen instances in which teen sexual activity declined after an aggressive education effort on condom failure rates and the dangers of sexually transmitted diseases.

"We feel there is very clear data that show that sexual activity is probably more risky behavior for an adolescent than smoking," said McIlhaney, who will run an educational session with Lubbock teachers and nurses Monday. "I don't think parents want their young people to become sexually active."

Abstinence educators aim to instill greater self-esteem in adolescents so they will have the courage and creativity to reject negative peer pressure. The easiest way to keep out of trouble, Ainsworth told the girls, is to "stay off your knees, stay off your back and keep your clothes on." And there is nothing cool about a young man in college preying on a 14-year-old girl, he added.

In large measure, medical professionals agree with Ainsworth. "Abstinence is the 100 percent effective way of not getting an STD or pregnant," said Vilka Scott, a disease intervention specialist at the Lubbock Health Department. "I strongly encourage abstinence."

But it would be irresponsible to stop the lesson there, she said. Abstinence may be the gold standard, but she also tells young people that delaying the onset of sexual activity, reducing the number of partners and using a condom greatly reduce risk.

"Telling people, 'Don't drink and drive,' doesn't make them go out and get drunk," she said. "I don't think information leads to bad decisions. I think it empowers individuals to make their own responsible decisions."

Like Scott, Tustin suggested that the abstinence-only approach does not give teenagers credit for being able to digest nuanced messages.

"Parents underestimate the knowledge kids have and the pressure they are under," she said. "They would be horrified if they knew what their kids know about drugs and sex."

One thing Ainsworth and Tustin agree on: Adults have failed the children of Lubbock.

"If parents think their kids are exposed to too much sexuality, they shouldn't have Britney Spears come to town," said Tustin, who was flabbergasted that tickets for the young sexpot's concert there sold out in 70 minutes. "You can't say to kids 'Don't have sex' and then let 12-year-olds stay out at a teen dance club until 11 at night."

The small band of rebels on the youth commission began to push for changes in the school curriculum more than a year ago. Last summer, several commission members took a Red Cross course on sexuality in the hope that they could do some teaching on their own outside school. In October, they organized a community forum sponsored by MTV that filled the city council chambers.

The session began with a short video in which pop star Tweet describes "nine things you need to know before you're good to go." The tips include getting regular checkups, learning about sexually transmitted diseases, using a condom and speaking candidly with sexual partners.

Some parents and students voiced dismay. "It was like a promotional video: Here are fun ways to do it," said Blake Williamson, 15. "The video made it sound like everybody's doing it -- you just need this information."

John Norris, the MTV correspondent moderating the forum, said a recent poll showed that 84 percent of teenagers wanted a comprehensive sex education curriculum and that 63 percent were not getting information they say they need. The students' questions seemed to illustrate his point.

Could a virgin conceive, one asked. Another asked: If a mother has AIDS, will the baby also contract the virus? Is the HIV virus spread by kissing? What about chlamydia? Would a girl with genital herpes infect her child during delivery? Can a woman get pregnant having sex with her clothes on? Do two condoms work better than one?

For youth commission member Maranda Buchanan, the forum was further proof that the abstinence-only curriculum had failed many of her peers.

"I knew this many people were having sex, but I didn't know so many were getting sick and pregnant," said Buchanan, 17. "Lubbock is in need of sex education."

High school student Shelby Knox asks a question at a forum on sex education in Lubbock, Tex.Corey Nichols, left, of the Lubbock City Youth Commission introduces MTV's John Norris at forum on sex education. Nichols says Texas's abstinence-only curriculum has failed.