IN AN IRONIC TURN OF EVENTS, the state-wide sex ed program may be to blame for an increased risk of STDs and the rising number of Portland teens engaging in potentially harmful sex. For decades, sex ed programs have had pregnancy prevention at their core. But the alleged success of these programs, measured in the ebbing number of teen pregnancies, may be masking a dangerous reality: More and more teens are engaging in forms of sex that are high conductors of diseases like chlamydia, herpes, and AIDS.

"My friends are having oral sex and anal sex just so they won't get pregnant," said Brook, a precocious 14-year old who asked that her last name not be used. She stood in the sunlight at Riverside Park on a recent afternoon, her boyfriend's arm wrapped casually around her waist. "It's like there's too much pressure to have sex, so they do other things to avoid it."

What teens interviewed don't seem to realize is that by avoiding intercourse they may be avoiding unwanted pregnancies, but they are not sidestepping other long-term dangers. Social workers and school administrators who work with teens are putting the blame squarely on the shoulders of limited education programs.

"They're learning in abstinence-only classes that as long they don't have vaginal sex, they won't get pregnant," said Jon Benson, education and training manager for Portland's Planned Parenthood office. Benson also studied behavioral science at the University of Chicago. "They do think oral sex is safe, and it's not. They can get genital herpes, gonorrhea, and syphilis."

Oregon law mandates that schools teach children about HIV and AIDS as well as Hepatitis B and other STDs, but it does not provide a curriculum or any guidelines on how these topics are taught.

"The problem is that not all schools are using the best programs," said Brad Victor, HIV/STD Coordinator for the Oregon Department of Education. "And some teachers just aren't comfortable talking about sex." He continued: "It's like any other subject: some people are bad science teachers."

While the direct links between deficient education programs and resulting incidents of STDs are speculative, the rising spread of those STDs are alarming. While pregnancy rates have dropped from 28.4 per 1,000 teens in Multnomah County in 1990 to 20.1 per 1,000 in 1999, they say cases of gonorrhea and chlamydia have stabilized, at best. They remained at about 15 cases per 1,000 teenagers tested since 1995, with a slight rise again this year.

But the Centers for Disease Control and Prevention (CDC) reported that as many as one in 10 teenage girls tested positive for chlamydia, and 46 percent of new cases are among teenagers.

According to state health official Dr. Mark Loveless, herpes is by and far the most prevalent disease among teens. Exact numbers are not obtainable, however, as Oregon law does not permit physicians to report incidents to the state. Even so, the CDC reports that herpes simplex virus type 2 is up 30 percent since the 1970s, and teens are five times more likely to have it now than they were then.

Despite the soaring numbers of STDs and healthy number of teens engaging in sex, the state's sex ed mandate continues to encourage abstinence-based programs. Nationwide, at least two-thirds of the high schools are using abstinence-based programs similar to those in Oregon. Many of the programs add information about how teens can protect themselves, but in Oregon, it's up to the individual school, creating a patchwork of complete and incomplete sex ed programs that varies from school to school.

In Portland, nearly one half of the high schools sponsor an ongoing relationship with Planned Parenthood. But again, these programs tend to be limited to pregnancy prevention and, according to Benson, only occasionally do schools permit curriculum that addresses fundamental issues such as responsible decision-making.

He adds, "Beaverton and Hillsboro won't let us anywhere near [their schools]."