Scenes of smoking and drinking should be considered when movies are being rated, but such scenes alone should not automatically earn movies an "R" rating, parents said in a new survey.

HealthDay News reported March 3 that researchers surveyed parents of children ages 9 to 15 and found that 66 percent believed that alcohol should be factored into the Motion Picture Association of America's (MPAA) rating system, while about half said that smoking should be a factor in rating movies.

However, only 42 percent of parents surveyed said that depictions of alcohol use alone should warrant an "R" rating, and about one in four parents said that smoking scenes should earn films an automatic "R."

"I think our study suggests that researchers and public-health advocates need to do a bit more work to educate parents about the relationship between movie smoking exposure and children's initiation, and to motivate and assist them to monitor their children's movie viewing," said lead researcher Meghan Longacre of the Hood Center for Children and Families at Dartmouth Medical School.

Public-health advocates have petitioned the MPAA to include smoking in its rating system, and MPAA has said that it would consider smoking scenes -- but not alcohol depictions -- alongside other factors in determining ratings.

The study was published in the March 2009 issue of the Archives of Pediatrics and Adolescent Medicine.