Oh this makes me sooo sad. Both of my boys came from people who had less common sense than a rock. Scooter's mother has had 9 litters that I know of, and the kittens always wind up at the SPCA. I offered to take his mom to get spayed, but the owner said no.
Clyde's mother is the same way. He was one of 13 kittens in his litter, and from what I hear there has been at least 3 litters since him. It just breaks my heart because my boys are lucky, but most of their relatives arent.
I agree wholeheartedly that there should be a test or something before people get pets or have kids!