"Media helps shape the social script for teenagers. Most parents know that. This is just good research to confirm that," Albert said.

Still, U.S. teen pregnancies were on a 15-year decline until a 3 percent rise in 2006, the latest data available. Experts think that could be just be a statistical blip.

And Albert noted that the downward trend occurred as TV shows were becoming more sexualized, confirming that "it's not the only influence."

Psychologist David Walsh, president of the National Institute on Media and the Family, cited data suggesting only about 19 percent of American teens say they can talk openly with a trusted adult about sex. With many schools not offering sex education, that leaves the media to serve as a sex educator, he said.

"For a kid who no one's talking to about sex, and then he watches sitcoms on TV where sex is presented as this is what the cool people do," the outcome is obvious, Walsh said.

He said the message to parents is to talk to their kids about sex long before children are teens.

Parents also should be watching what their kids watch and helping filter messages sex-filled shows are sending, he said.