That's like saying 10 year olds who play m rated games will be affected mentally. 10 year olds aren't legally allowed to buy m rated games; teens wouldn't be allowed to buy weed. Only difference is I doubt they could convince mommy or daddy to buy it for them. I don't smoke it personally, I don't think many people have a legitimate reason to other than to get high, but considering how harmless it is, I don't see why it is illegal. As OP said, the only dangerous thing about weed is getting busted for possession. Our country (USA) needs to back off when it comes to non-violent offenders' punishment in general, and I think weed is a decent first step.