Whatever one does behind closed doors is their perogative. But, to state a generalization that marijuana use is safe, is wrong. For some individuals, the drug can be fad and in a couple of months it's over. To others, it can be dangerous. Just like alcohol. Some people can be "social" drinkers while others become addicted. Could there be a gene that predisposes people to addiction? My guess is yes.
A recent study suggests that marijuana use can increase the chance of getting schizophrenia by 6. Just one of many studies that are going on....as you tell people marijuana is safe. Be careful my friends.