Too much television, low self-esteem, disappointing grades and poor family relationships can be a formula that adds up to early teenage sex, according to a new study.

"If you add up all the factors, you get a much more powerful predictor of who has sex and who doesn't," said Dr. Janet Hyde, of the University of Wisconsin, who headed the research team.

"One thing probably by itself is not going to do it, but by the time you get two or three risk factors, things start to go downhill," she added.

Hyde and her team studied 273 teenagers between the ages of 13 and 15. About 15 percent of them had early sex.

"Kids who engage in early sexual activity are much less likely to use any kind of protection which increases their risk for teen pregnancy and acquiring sexually transmitted diseases," Hyde said.

One of the best predictors for early teen sex is television viewing, in part because television programs portray higher levels of sexuality for teens and adults than exists in reality, the researchers said.

"Communications theorists say that as we watch a lot of material like that, we come to believe that it is reality. In this case, kids who watch a lot of TV come to believe that all the kids really are having sex, so they're going to do it too or they are going to be the odd one out," Hyde, who reported the finding in the Journal of Youth and Adolescence, explained.

TV also often does not portray the negative consequences of sex, such as unexpected pregnancy or sexually transmitted diseases, she said.

But it is not the only risk factor for teens to start having sex before age 15.

Girls who had been sexually active early had lower self-esteem, poor relationships with their parents, lived with either a single mother or step-parent, showed signs of attention-deficit hyperactivity disorder (ADHD), underachieved at school, and watched more television.

Boys who had early sex were further into puberty, had lower self-esteem, showed signs of ADHD and oppositional defiant disorder (ODD), had poor relationships with their parents and also watched more television than other boys.

The researchers recommend that all of the risk factors for early teen sex be addressed and that parents participate in the process, as well as teachers and counselors.

They also called for comprehensive sex education programs so teens can protect themselves if they have sex.

"If we have comprehensive sexuality education so that kids really can make informed choices and protect themselves, that's a much better strategy," said Hyde.

(China Daily/Agencies November 25, 2008)