The Recording Industry Association of America, which represents the U.S. recording industry, declined to comment on the findings.

Benjamin Chavis, chief executive officer of the Hip-Hip Summit Action Network, a coalition of hip-hop musicians and recording industry executives, said explicit music lyrics are a cultural expression that reflect "social and economic realities."

"We caution rushing to judgment that music more than any other factor is a causative factor" for teens initiating sex, Chavis said.

Martino said the researchers tried to account for other factors that could affect teens' sexual behavior, including parental permissiveness, and still found explicit lyrics had a strong influence.

However, Yvonne K. Fulbright, a New York-based sex researcher and author, said factors including peer pressure, self-esteem and home environment are probably more influential than the research suggests.

"It's a little dangerous to just pinpoint one thing. You have to look at everything that's going on in a young person's life," she said. "When somebody has a healthy sense of themselves, they don't take these lyrics too seriously."

David Walsh, a psychologist who heads the National Institute on Media and the Family, said the results make sense, and echo research on the influence of videos and other visual media.

The brain's impulse-control center undergoes "major construction" during the teen years at the same time that an interest in sex starts to blossom, he said.

Add sexually arousing lyrics and "it's not that surprising that a kid with a heavier diet of that . . . would be at greater risk for sexual behavior," Walsh said.

Martino said parents, educators and teens themselves need to think more critically about messages in music lyrics.

Fulbright agreed.

"A healthy home atmosphere is one that allows a child to investigate what pop culture has to offer and at the same time say 'I know this is a fun song but you know that it's not right to treat women this way or this isn't a good person to have as a role model,"' she said.

On the Net: —Pediatrics: www.aap.org/

—National Institute on Media and Family: www.mediaandthefamily.org/

—Teen sexual health: www.sexetc.org/