My dad and his buddies used to hunt a place in east tennessee up close to the kentucky border. They were way out in the sticks, they said there was just one family that lived within a few miles of their hunting camp and that this family lived in a kind of filth and squalor that was hardly imaginable. But, they had some interactions with the guy and his wife and they seemed to be friendly enough. They had several children, all of which were physically or mentally handicapped in one way or another. A couple years after first meeting them they found out from some locals that the husband and wife were brother and sister, just the thought of it gives me the willies.