News Release

Having oral sex increases likelihood of intercourse among teens

Peer-Reviewed Publication

University of California - San Francisco

Half of teens who have oral sex during the ninth grade will have intercourse by the end of the 11th grade, and most sexually active teenagers will begin engaging in oral sex and sexual intercourse within the same six-month period, according to findings from a new survey conducted by researchers at UCSF and UC Merced.

The study is the first to track teens' sexual behavior over time to determine whether oral sex increases the likelihood of having sexual intercourse or acts as a protective measure delaying the onset of further sexual activity. The data, explain the researchers, yield important information about adolescent sexual development and the need to deliver more comprehensive sex education programs.

"Health care providers, health educators and parents need to not be shy about discussing oral sex with teens," said Bonnie Halpern-Felsher, PhD, senior author of the study and a professor of pediatrics at UCSF. "I see most of the health policies out there and guidelines for preventive services talking about sex generally, but they do not specify oral sex. That is an important distinction because teens don't consider oral sex to be sex, and many are not aware of the risks involved."

Study results are published online by the Archives of Pediatrics and Adolescent Medicine, available at, and also will appear in the March 2011 print issue of the journal.

"Our study demonstrates that through its relationship with intercourse, oral sex contributes to the total risk associated with sexual activity among teens, including sexually transmitted diseases and pregnancy," said Anna Song, PhD, first author of the study and an assistant professor of psychological sciences at UC Merced. "Understanding teen sexual behavior is so important because incorrect assumptions about how and why teens engage in sex can undermine interventions that aim to curb these negative outcomes."

The researchers followed more than 600 students at two northern California high schools from the ninth grade through the end of 11th grade. All participants received their parents' consent to participate. From 2002 to 2005, the students completed a survey every six months during class time about their sexual experiences. Responses were consistent across different ethnic groups, socioeconomic levels and genders.

Among teens who reported becoming sexually active during the three-year study, most said they had intercourse for the first time after or within the same six-month period of initiating oral sex. According to Halpern-Felsher, this indicates oral sex is influencing the onset of riskier sexual behavior, underscoring the need to encourage open, honest discussion about sexual activity.

"We need to make sure teens know that if they do choose to have oral sex, certainly it does involve less risk than intercourse, but it's not risk-free," Halpern-Felsher said. "We also have to be sure to ask teens if they have any questions. It sounds simple, but it is a very important step that parents and healthcare providers should be taking."

Teens who had engaged in oral sex by the end of ninth grade were at the highest risk of having sexual intercourse during high school. They had a 25 percent chance of having intercourse by the end of ninth grade and a 50 percent chance by the end of 11th grade, with most engaging in both oral sex and intercourse during the same six-month period.

In comparison, adolescents who delayed oral sex until the end of 11th grade had only a 16 percent chance of having intercourse by the end of that school year. The researchers explain that, based on these findings, the first two years of high school appear to be a particularly vulnerable period.

"We don't want parents to hear about these findings and say, 'Thanks for the information. I'm locking up my teen until graduation,'" Song said. "The most effective reaction is to use this knowledge to have an informed conversation with kids that addresses different types of sexual behaviors, including oral sex."

In a previous study of adolescent sexual behavior, Halpern-Felsher found that at least 20 percent of adolescents have oral sex by the end of ninth grade and more than half of teenagers 15 to 19 years old engage in oral sex with members of the opposite sex.


The study was funded by grants from the National Institute of Child Health and Human Development, the William T. Grant Foundation and the Asian American Center on Disparities Research.

UCSF is a leading university dedicated to promoting health worldwide through advanced biomedical research, graduate-level education in the life sciences and health professions, and excellence in patient care. More information is available at

UC Merced opened Sept. 5, 2005, as the 10th campus in the University of California system and the first American research university of the 21st century. The campus significantly expands access to the UC system for students throughout the state, with a special mission to increase college-going rates among students in the San Joaquin Valley. It also serves as a major base of advanced research and as a stimulus to economic growth and diversification throughout the region. Situated near Yosemite National Park, the university is expected to grow rapidly, topping out at about 25,000 students within 30 years.

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