Two-thirds of parents said they are very concerned about sex and violence the nation's children are exposed to in the media, and there would be broad support for new federal limits on such material on television, said a survey released Tuesday.

Yet the report released by the nonpartisan Kaiser Family Foundation found that two in three parents said they already closely track their children's television viewing and use of the Internet and video games.

Only one in five parents conceded they should do a better job -- about the same fraction who said their own children see a lot of inappropriate material. Parents, teachers and friends have far more influence over children than the media, respondents said.

"There's a common assumption they (parents) feel overwhelmed, behind the curve when it comes to their kids and the Internet, like they're at a technological disadvantage," said Vicky Rideout, who directed the Kaiser study. "We didn't find that in this survey."

But parents "are fooling themselves" if they believe they have that much control, an expert on the effect the media have on children said during a panel discussion that accompanied the release of the report.

"Parents think they are controlling the media -- kids say they are not," said Victor Strasburger, a professor of pediatrics at the University ories in a 1998 Kaiser survey. Black and Hispanic parents were more likely than whites to voice that concern.

About three-fourths rated exposure to inappropriate material as one of their top concerns as a parent, or a big worry. Television and the Internet were most frequently cited as the leading sources of angst.

While two-thirds said they closely watch their children's media use, 18 percent said they should do more while another 16 percent said such monitoring is not necessary. Of those who said they need to do more, most said they haven't because media exposure is too widespread or they were too busy.

The report also found:

--One in four said the media are mainly a negative influence on their children, about a third said they are mainly positive and slightly more than that said they have little impact.

--Three in four with children 9 or older who use the Internet at home said they know a lot about what their children do online. Most said they have checked their children's e-mail, profiles on social networking sites like MySpace, and the Web sites they visit.

--About four in 10 who own televisions with V-chips -- which can block certain television shows -- were aware they had the technology. Of those, nearly half said they have used it.

The Kaiser survey of 1,008 randomly chosen parents of children age 2 to 17, has a margin of sampling error of plus or minus 4 percentage points. It was conducted last Oct. 2-27 by Princeton Survey Research Associates International, a private firm.