Why do we return time and again to those glamorous Hollywood dramas of days gone by? Perhaps because they remind us of a more innocent time, before the polar ice caps melted, before instant messaging replaced the spoken word, before tobacco caused cancer. Bogart, Bacall, Davis, Crawford are all but unimaginable without a cigarette in hand. 

But a growing chorus of medical professionals and other concerned citizens is pressuring the MPAA and the major studios to curtail on-screen smoking in films marketed to children. 

 According to a study released last week, funded by the National Cancer Institute and American Legacy Foundation and entitled "Exposure to Smoking Depictions in Movies: Its Association With Established Adolescent Smoking," youths exposed to movie smoking double their risk of becoming adult smokers.

Earlier this year, the MPAA agreed to consider smoking as a factor in rating movies. And Disney announced last month that it would ban smoking from its future family-oriented films. If this semi-ban actually takes effect, it will be interesting to repeat the NCI study in a decade or two and see what impact limiting on-screen smoking actually has on adolescent off-screen behavior.