I think the biggest reason it might be a gateway drug is because it is lumped in with drugs much more severe.
Kids hear it in the same sentence with heroin and meth. DONT DO IT! IT WILL KILL YOU! Then they smoke pot for the first time and realize it is less intoxicating than alcohol.... they probably assume people were exaggerating about the hard drugs as well.
That's a good point but I do believe that kids are smarter than that to understand that hard drugs are just that: hard on your body and hard to impossible to stop once use quickly becomes abuse. Back in the day when drugs were made illegal, I have heard that pot was lumped into the same category as the really hard drugs so the blacks would not use it as they often had or wanted sex with white women when they did. That seems far fetched but I believe there is more truth to it than not.
