Aug. 5, 2008 -- More than 12% of children aged 10 to 14 are watching R-rated violent movies, prompting researchers to call for an overhaul of the movie rating system and for more involvement from pediatricians.

A study by Dartmouth researchers, published in the journal Pediatrics, focuses on 40 movies rated R for violence and shows that these movies have been seen by about 12.5% of American children between the ages of 10 and 14. The study was conducted in 2003 among 6,522 adolescents aged 10-14 and included top box-office movies from 1998 to 2003 that were rated R for violence.

Some movies scored higher. The R-rated Scary Movie, starring Carmen Electra, had been seen by 48% of children aged 10 to 14.

"We know so much about the harmful effects of exposure to violent media content, but how much exposure children actually get has largely been ignored," says Keilah Worth, PhD, the lead author on the study and a post-doctoral fellow at Dartmouth Medical School and Dartmouth-Hitchcock Medical Center's Norris Cotton Cancer Center.

Researchers point to an existing body of research that documents the negative effects of violent media on children. "A clear picture has emerged that exposure to violent media increases the likelihood of aggressive thoughts, emotions, and behavior," the authors write.

The movie rating system, designed 40 years ago when the only way to see a movie was in a theater, no longer is adequate, according to researchers. These days, with DVDs, pay-per-view, and movies that are downloadable off the Internet, children have more access than ever to adult media. Many parents likely are not aware of what their kids are watching.

Researchers call for pediatricians to play a more active role by educating parents about how many children are actually watching violent movies and the harmful effects of that exposure. Doctors could also assist parents with technology, such as the V-chip, to restrict access to media.

"Ratings need to be more prominent on all movies, whether they are seen in theaters or purchased in the store, and we need clearer messages to parents," James Sargent, MD, professor of pediatrics at Dartmouth Medical School, says in a news release.