My dad is actually a police officer now, but I have heard from my uncles that he was once quite the herb smoker in college. However, whenever he caught me with a bag of weed when I was living under his roof, I would have hell to pay. My mom also doesn't use drugs, but from arguements I have heard between her and my dad about my drug use when I was in high school, she apparently had done some exploring with cocaine in college.
My mom is somewhat cool about it. She doesn't want me to be doing anything serious like heroin or even eating prescription pills (thanks to my criminal offense that gave me the grand opportunity to sit in the very luxurious county jail for a few months). But as far as weed goes, she's sorta like, "If you're going to smoke it and then be around me, just don't act retarded".
But now that I have moved out, my family is so unpredictable that I wouldn't doubt if my parents are puffing on the ganja right now.