I can't imagine any way of growing weed in your parent's house without getting caught unless your parents are practically retarded. Shrooms you might be able to get away with, but probably not weed. At the very least, it would be extremely risky. hehe
Plus there are moral implications you may not have considered. It's not totally unheard of for people to have their homes confiscated if they get caught growing or distributing illegal drugs for example. People never think they will be caught, but it's always a possibility. It's one thing to jeapordize your own property by taking a calculated risk, but it's another thing entirely to possibly compromise another persons property without their knowledge or consent.
I am a fan and supporter of marijuana, but I would still be REALLY PISSED if I found out somebody was growing on my property without my consent.