Youth who watch a lot of movies with cigarette-smoking characters - whether the films are rated R or PG-13 - are more likely to start smoking themselves, researchers suggest in a new study.

The report's lead author said the finding supports the idea that it's the smoking itself - and not the sex, profanity or violence that may go along with it in certain films - that influences youth to take up the habit.

"Movie smoking seems to be just as impactful if it's packaged in a PG-13 movie as opposed to an R movie," said Dr. James Sargent, from the Geisel School of Medicine at Dartmouth in Lebanon, New Hampshire.

"I really think it's a 'cool' factor. The more they see it, the more they start to see ways that (smoking) might make them seem more movie-star," he told Reuters Health - even if the effect is subconscious.

Above, Brad Pitt starred -- and smoked -- in "Fight Club."

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