This is the first study which links viewing habits with teen pregnancy, said lead author Anita Chandra, a behavioral scientist. Teens who regularly watched sexually explicit shows were more likely to become pregnant as those who watched such programs off and on.

Previous research had already concluded that, watching profuse sex on TV can manipulate teens to have sex in immaturity.

Shows, that propagate sexual behavior without the risks can direct teens to have vulnerable sex “before they’re ready to make responsible and informed decisions,” Chandra said.

The study involved 2,003, 12 to 17 year-old girls and boys nationwide, inquired by telephone about their favorite TV programs in 2001. Teens were re-interviewed twice, the last time in 2004, and asked about pregnancy. Among girls, 58 became pregnant during the follow-up, and among boys, 33 said they had gotten a girl pregnant.

Teenagers who watch TV shows which found to have lots of sexual content were more active sexually than their other group members participating in the study. The programs included “Sex and the City,” “That ’70s Show” and “Friends.”

Pregnancies were two times as common among those who admit they watched such shows regularly, compared with teens who said they hardly ever saw them.

Bill Albert, chief program officer at the nonprofit National Campaign to Prevent Teen Pregnancy, praised the study and said it “catches up with common sense.”

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