I do allow some of my cats outside in our fenced yard if I'm there to watch them! They like to play in the garden and I've never had a problem-but if they wheren't staying in my yard that would be the end of thier outdoor time! For the reasons already mentioned, plus I don't like cleaning up after other peoples pets when they go in my yard, so why should my neighbors have to pick up after mine? Growing up the cats where always outside, and we had one cat someone kicked in the head so hard it ruptured the eye, and we ended up with a huge emergancy vet bill to have the eye removed, and that poor cat was never the same after that, never again would I risk that happening to my cats. When I have a place of my own, I intend to fence in the back yard, and "cat proof" my back yard with a cat fence at the top and cement the bottom of the fence in to keep the cats in my yard yet still allow them to go outside and enjoy the nice weather.