In a study of 100 young girls it was determined that smoking marijuana doubled the chance of her turning into a crack whore. Is that what you want for your daughter? Hmm?
Also consider this, while marijuana may indeed not be very harmful in and of itself, many fine police officers, DEA agents, and FBI agents have lost their lives against hardened criminals selling this illegal drug.
It is also a Gateway drug. Sure it is not very addictive, but since it is illegal people, consort with these criminals who sell other more dangerous drugs.
If you can't see how dangerous it is with these simple facts, I feel you are lost cause.
Ok to be honest, only the first one was made up. The rest are real objections to marijuana.