In the beginning, yes, the show, as well as the boys were too young to address controversial issues. It's the first impression that leaves the greatest one after all. The boys aren't supposed to be perfect, screaming and yelling and beating each other up. As the boys grow, the show grows with them. Do you really think that the viewers would sympathize with Malcolm if he was smoking and bed-hopping in middle school? After Malcolm learned to drive and looked older too, it was okay for him to go farther relationships with girls. Adressing a contreversial topic like that is walking on eggshells for the producers. We've known Dewey for years now, and his personality has evolved. Mom and dad have finally learned that he's capable of being as devious as his brothers, so taking a puff wouldn't exactly be his first offense. Think of it this way, if three random pre-adolescent boys kikced off their tv series with an episode about smoking, gun usage, or unsafe sex and then tried to have a normal episode right after, wouldn't you be surprised? In order to teach something, the characters have to be well known, and the show has to have ripened.