There’s compelling evidence to support the claim that smoking in the movies encourages young people to take up the habit.

A new study by the Norris Cotton Cancer Center at Dartmouth Medical School suggests that slapping an R-rating on movies that depict smoking will reduce the likelihood kids will take up the habit with all of its known medical consequences.

Researchers say the threat of an R-rating would force Hollywood to eliminate smoking from films targeted at the youth market. Their research concluded that it would reduce adolescent smoking by as much as a fifth.

The study is published in the August issue of the journal Pediatrics.