A new study claims to have identified a link between the type of media teenagers watch and their propensity to have sex.
The testers examined 1,017 black and white teenagers from North Carolina at 12 to 14 years old and again two years later.
The children were asked about their favourite forms of entertainment, including television shows, movies, songs and magazines. They were also quizzed on their attitudes to sexual behaviour.
Students who had a high "sexual media diet" were 2.2 times more likely to have sex than those who watched less racy material. The effect was higher among white students than black students.
"Teens are defaulting to entertainment media for sexual information because they are not getting this information in other places," said Dr Jane D. Brown, a professor in the School of Journalism and Mass Communication at the University of North Carolina.
Dr Brown is the principal investigator of the study, which was funded by the National Institute of Child Health and Human Development.
"Unfortunately, the media are not the best sex educators," she said. "The media tend to leave out the crucial three Cs: commitment, contraception and consequences."
Dr Brown maintained that the media, schools, parents and paediatricians need to provide more accurate and timely sex information to teens.
"Otherwise, the media will continue to serve as a kind of sexual super peer that does not have the best interests of young people in mind," she argued.
The results form part of a five-year study into how the media influences teenagers' appetite for sex.
But the study also showed that, however strong the media influence may be, parental attitudes to sex are far more important.
Teenagers who reported that their parents did not want them to have sex were less likely to try it by the time they were 16 years old than those who perceived less parental disapproval.
The study was published in Pediatrics magazine. In an editorial, paediatrician Dr Victor Strasburger said that paediatricians, teachers, parents and the entertainment industry must think about sexual activity differently to how they confront other risky behaviours to which teens may be attracted.
"Remember that sex is not like drugs," Dr Strasburger wrote. "We want our children to have happy, healthy sex lives - when they are older, not when they are 13."
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