Parents and health professionals should help teens prepare for and cope with the emotions attached to sex, say Sonya Brady, PhD, and Bonnie Halpern-Felsher, PhD.
The two researchers work at the University of California, San Francisco.
They studied a diverse group of 273 sexually active students at two California public schools between 2002 and 2004.
The students, 56% of whom were girls, all reported having had vaginal and/or oral sex by spring of 10th grade.
Of the students, 116 said they had had only oral sex, 43 said they had had only vaginal sex, and 114 said they had had both.
Consequences From Teen Sex
For the study, the students completed surveys every six months between 9th and 10th grade about the consequences they experienced from sex.
Overall, the teens reported positive consequences -- such as pleasure, popularity, and stronger relationships.
But a sizeable percentage noted negative consequences such as feeling used, getting pregnant, contracting a sexually transmitted infection, or feeling bad about themselves.
Those reporting at least one negative effect included 31% of those who had had only oral sex, 58% of those who had had only vaginal sex, and nearly 62% of those who had had both.
Girls were more than twice as likely as boys to say they felt bad about themselves. Girls were also more than three times as likely to say they felt used as a result of having sex.
Those findings may partly stem from society's double standard about sex.
"These findings are consistent with research showing that boys are encouraged to be sexually experienced, whereas girls are encouraged to restrict sexual behavior," the researchers write.
Boys were more likely to say their popularity rose when they became sexually active.
But they were also more likely to report a pregnancy or sexually transmitted infection as a result of their sexual activity.
The reasons for those findings aren't clear. The boys may have been more sexually active, had more partners or risky sex, or been more willing to admit those consequences, say the researchers.
Teens may need help in coping with the emotions that surround sex, the researchers say.
They encourage health professionals and other adults to talk with adolescents "about how decisions to engage in any type of sexual activity may have important consequences."
The study has limits. For instance, it's not clear if the results apply to all sexually active 9th and 10th grade students.
Also, the surveys didn't label the listed consequences as good or bad; the researchers classified consequences as positive or negative without teen input.
"We do not know whether consequences were viewed as positive or negative by adolescents," write Brady and Halpern-Felsher.
SOURCES: Brady, S. Pediatrics, February 2007; vol 119: pp 229-236. Reuters.
By Miranda Hitti
Reviewed by Louise Chang