Darth Vader. Captain Hook. Lex Luthor.

06/20/2008 05:12 am ET | Updated May 25, 2011

Hollywood and moviegoers love a good villain. However, the love affair ends when that bad guy starts to smoke. Again and again, public opinion polls show disapproval for movies that unnecessarily contain smoking, especially when the movie is intended for a youth audience.

Why? Because studies prove that 35 percent of new smoking in children ages 9-12 can be attributed to exposure to smoking in movies -- and that exposure to such imagery predicts established smoking behavior in adolescents. This means that Hollywood recruits approximately 390,000 new smokers annually -- nearly enough to replace all of the smokers that tobacco kills in America each year.

So why, then, do the bad guys in this year's blockbusters have such a penchant for tobacco?

The Incredible Hulk is just the latest to have its antagonist smoke on screen. Iron Man, Indiana Jones and even Speed Racer have all shown villains with tobacco.

And don't think kids don't notice. Studies show that approximately 60 percent of youth exposure to smoking onscreen is found in G, PG or PG-13 movies.

Some would argue that this is character building, but I doubt any moviegoer has ever left a theater thinking, "that character would have been more enjoyable or realistic if they had smoked."

Others argue that bad guys smoking aren't the same as when good guys light up. But a Dartmouth study in 2002 proved that it doesn't matter who smokes in films -- heroes or villains. If the movie has smoking, children are influenced.

In light of all of this evidence, character-building really needs to happen with the studios themselves and the Motion Picture Association of America. Responding to pressure from advocacy groups in 2007, the MPAA announced that it would "consider" smoking as a factor in its ratings. But since then, it hasn't honored its word.

According to analysis by public health advocates of top box office films released in the 12 months following the MPAA announcement, 38 percent of G and PG movies and 58 percent of PG-13 movies featured tobacco. More than half of all top box office films with smoking in the 2007-2008 time period were youth-rated.

Enough is enough. It is time the MPAA assign any movie with unnecessary smoking an R rating. The governing body already gives R ratings to films that depict violence, profanity, drug abuse and sex. While these may seem more serious, in reality, cigarette smoking is the single most preventable cause of premature death in the nation.

That's why leading public health groups are working to minimize the extent to which youth are exposed to smoking in films. This starts with an automatic R rating but also includes certifying that no pay-offs between the tobacco industry and studios exist, and requiring strong anti-smoking ads at the beginning of films.

But we cannot do it without the help of the movie studios and the MPAA. Parents and health advocates need more than just lip service from Hollywood. We need a partner who will honor what they say and prioritize our children's health over profits.

Otherwise, to co-opt the Hulk's famous line, "You wouldn't like us when we're angry."