In a recent Time Magazine story, the author cited a recent study done by North Carolina researchers.
I have also read of studies that say adults who drank with their parents as teens are more likely to be problem drinkers in adulthood. Because of that I don't think it's a smart move. Self reported data can't always be trusted. ESPECIALLY when it comes from teens. My friends who's parents let them drink small amounts of alcohol with them all drank when their parents weren't around. My parents don't drink at all and I didn't even try it until I left home. I didn't drink nearly as much as my friends did during college either.
My daughter's dad has said before that he would let DD try alcohol AND marijuana if she wanted to. I am completely not OK with that and if I ever found out he did that he will be in deep crap. I don't have a problem with responsible marijuana use, but nearly everyone I know who has had a major problem with it started in their teens. I hope he feels differently when she gets older.