I don't get it, what makes you think marijuana can't be a carcinogen when anything you burn in excess and inhale can cause it? Since there are fewer studies, one can not conclude that MJ is cancer free. Benzpyrene is in MJ and cigs and causes cancer so I wouldn't go off and say MJ is that oh-so perfect substance. My brother is a chronic MJ smoker and is paralyzed from a stroke. He smokes cigs too but he failed to possess the motivation to rehabilitate and walk again which the doctors said he could do if he just applied himself. I blame the Marijuana for that lack of motivation, which will eventually kill him. Let's stop putting MJ on some pedestal and get real. Shits nice to have but should only be used in moderation just like anything else, except sex.