WASHINGTON (By Laura Sessions Stepp, Washington Post) September 15, 2005 - Slightly more than half of American teenagers, ages 15 to 19, have engaged in oral sex, with females and males reporting similar levels of experience, according to the most comprehensive national survey of sexual behaviors ever released by the federal government.

The report today by the National Center for Health Statistics shows that the figure increases to about 70 percent of 18- and 19-year-olds.

The survey, according to those who work with young people, offers one more sign that young women are more sexually confident than they used to be. A release by the center six months ago, based on the same survey results, showed that slightly more girls than boys have intercourse before they turn 20. In addition, other national data indicate that the same proportion of high school girls and boys have sex only one time with a particular person or have relationships with others that they are not romantically involved with.

"This is a point of major social transition," James Wagoner, president of Advocates for Youth, a reproductive health organization, said yesterday. "The data are now coming out and roiling the idea that boys are the hunters and young girls are the prey. It absolutely defies the stereotype."

The data also underscore the fact that, unlike their parents' generation, many young people -- particularly those from middle- and upper-income white families -- simply do not consider oral sex a big deal.

"Oral sex is far less intimate than intercourse. It's a different kind of relationship," said Claire Brindis, professor of pediatrics at the University of California-San Francisco. "At 50 percent, we're talking about a major social norm. It's part of kids' lives."

Bill Albert, communications director for the National Campaign to Prevent Teen Pregnancy, put the generational difference this way: "We used to talk about sex in terms of first base, second base and so on. Oral sex was maybe in the dugout."

Until now, said Brindis, who has worked in the field of adolescent health for 30 years, researchers, policymakers and politicians could turn only to anecdotal evidence or small samples in order to gauge sexual behavior. Policies and programs were put into place that may turn out to be ineffective and put young people more at risk for sexually transmitted disease.

The newly released data, gathered in 2002, are sure to stir debate over abstinence-only sex education. Supporters of such programs say they have resulted in young people delaying intercourse, but opponents say they simply have led young people to substitute other risky behaviors, especially fellatio and cunnilingus. The new data tend to support the latter view, showing that nearly one in four virgin teens has engaged in oral sex.

Many teenagers have fully accepted the idea that postponing intercourse is a good thing to do, Brindis said. When they weigh the advantages and disadvantages of intercourse versus other forms of sex, they decide that they are far more at risk with intercourse, both because of pregnancy and the greater risk of disease.

"They're very smart about this issue," said Brindis, "but they may not have been given a strong enough message around the risks of oral sex. Maybe we need to do a better job of showing them they need to use condoms." Oral sex has been associated in clinical studies with gonorrhea, syphilis, herpes and the human papillomavirus, which has been linked to cervical cancer. Condoms and other forms of contraception can be used to decrease the health risks of oral sex, but few teens use them.

"If a substantial number of young people are having oral sex, as these numbers indicate, this is a big concern," said Kristin Moore, president of Child Trends, a children's research organization that analyzed the center's most recent findings.

Child Trend's analysis breaks down the federal data by age, race and ethnicity, mother's education, family structure and income. Combined, these breakdowns show that oral sex is most common among white families in the higher-income brackets.

Many sexual health programs have focused on kids from lower-income families, Moore said. The new data suggest that those programs may need to be expanded to other groups.