Shows like Sex and the City were linked to teen pregnancies
Teenage girls who watch a lot of TV shows with a high sexual content are twice as likely to become pregnant, according to a study.
Boys watching similar programmes, like Friends and Sex and the City, were also more likely to get a girl pregnant, the research in Pediatrics found.
The study authors said limiting exposure to sexual content on TV might reduce teen pregnancies.
Experts urged parents to talk more openly with their children about sex.
Study author Dr Anita Chandra of the RAND Corporation said adolescents received a considerable amount of information about sex through television and the problem was that programmes such as these typically did not highlight the risks and responsibilities of sex.
Sexual content on TV has doubled in the last few years, especially during the period of our research. We found a strong association
Lead researcher Dr Anita Chandra
She said:"Our findings suggest that television may play a significant role in the high rates of teenage pregnancy in the US."
According to Dr Chandra, hers is the first study to show such a direct link.
The researchers interviewed 2,000 adolescents aged 12 to 17 three times between 2001 and 2004.
Teens who watched larger amounts of sexually charged TV shows were twice as likely to experience a pregnancy in the subsequent three years, compared with those with lower levels of exposure.
By the third interview, 744 of the teenagers said they had engaged in sexual intercourse and 718 of the youths shared with the researchers information about their pregnancy histories.
Of that group, 91 teens - 58 girls and 33 boys - were involved in a pregnancy.
Dr Chandra said: "Sexual content on TV has doubled in the last few years, especially during the period of our research. We found a strong association."
The US has one of the highest teen pregnancy rates among industrialized nations, with nearly one million adolescent females becoming pregnant each year, with the majority of these pregnancies unplanned, according to RAND.
Britain has Europe's highest teenage pregnancy rate.
Tory MP Nadine Dorries said it would be interesting to see if a similar study in the UK revealed a trend.
"Information such as this empowers parents when making difficult decisions as to what they do and don't allow their daughters to watch," she said.
Psychologist David Walsh, president of the National Institute on Media and the Family said many teenagers relied on the media to act as sex educator.
Dr Walsh said: "If you have a kid who no-one's talking to about sex and who then watches sitcoms on TV where sex is presented as 'this is what cool people do', the outcome is obvious.
"The message to parents is to talk to their kids about sex long before they become teenagers."
A spokeswoman from Brook said: "The causes of teen pregnancy in the UK are quite complex.
"There are a range of ways we can try to reduce the teen pregnancy rate, such as providing sex and relationship education and outreach and community services for young people.
"The idea of parents sitting down with their children and talking about the issues raised in these television programmes is a great one."