Washington ? The OC,” “Desperate Housewives” and other TV shows popular with teenagers generally have more sex than other programs, a study says.

TV executives say they’re not pushing sex on children and that if parents don’t want their kids to see certain shows then they have all the tools they need, including the “off” button.

According to the study released Wednesday by the Kaiser Family Foundation, the vast majority of TV shows – 70 percent – include some sexual content, with an average of five sex scenes per hour.

The study examined programming on ABC, CBS, NBC, Fox, WB, PBS, Lifetime, TNT, USA Network and HBO. Sexual content could be anything from discussions about sex to scenes involving intercourse.

The number of scenes involving sex has nearly doubled since 1998, the study said, from 1,930 to 3,783.

The study did not offer an opinion on whether sex on TV is harmful to children. But lead researcher Dale Kunkel said it’s generally established that TV influences kids.

“Their sexual knowledge, attitudes, behaviors are all shaped in part by the characters in stories that television conveys,” he said.

Kaiser released the study’s findings at a news conference with Sen. Barack Obama, D-Ill., followed by a panel discussion with executives from NBC and Fox, Commissioner Kathleen Abernathy, of the Federal Communications Commission, and others.

Tony Vinciquerra, president and chief executive officer of Fox Networks Group, said parents already have the controls they need on cable and satellite to block channels or programs they deem inappropriate.

Parents with regular over-the-air TV can use the V-chip, technology that’s built into televisions and works with an electronically coded rating system to identify programs that contain sex, violence or crude language.

Vicky Rideout, a vice president at Kaiser, said the number of shows that included a message about the risks and responsibilities of sex is still very small and has remained flat since 2002.