Why? Should "good parenting" also decrease the chances of a child drinking alcohol? Pot? Shrooms?
The apparent assumption here among many people that these substances are intrinsically bad is baffling to me. Where do you draw the line? Surely it can't be "legality", because several of the "schedule 1" drugs are completely harmless, and possibly even naturally occurring (in your own body!). If potential for bodily harm is the deciding factor, then we should be discussing alchohol "cures" looong before anything else. It is absurdly common and absurdly addictive.