21... i think that is a great age, simply because of the bodies development, experience, and laws on alcohol, so in the US it should be 21, only fair i think... plus by then people are more focused in their life, where an intoxicant like weed, causes some lifestyle changes... remember, think masses... i know people i don't want smoking... OMG

i mean hell it won't stop underage smoking... and let's be honest even though i started smoking when i was 11, i have watched it's affect on me, friends, and now that i'm older, friend's kids, ect... and while everyone is different i think it shouldn't be encouraged to children, which is what under 21 is... i mean its all shades of grey...