Okay, I have to butt in here.
I am a volunteer and an adoption coucilor at a VERY large shelter in the USA. We DO NOT adopt any cat to a home that lets it outside - at all. Why? Because the average life for an indoor-outdoor cat in the USA is 3 years. Indoor only cats? 18 years. Gee, isn't that reason enough?
And as for cats "naturally" needing to be outdoors. Hate to break it to people, but cats aren't native to the UK or the USA. In the wild, cats have miles of territory to themselves, in the USA, there are maybe 25 cats in the same area. That's not natural - and it's a risk. Not only that, but take into account dogs, cars, foxes, wolves, coyotes, and sick people who shoot and poison them. In their natural habitat, they never had to deal with these things. Putting them in a situation where they do is just cruel. Not only that, but they're destroying species that have no natural defence mechanism. So if you won't do it for the cats, do it for your environment.
FIV and FeLV is running rampant. There's a serious risk of rabies these days. The feline population is exploding, so if you have to let a cat outdoors, for heaven's sake, fix that baby! It's just not healthy for them, at all.
Now, I know some cats won't adapt to being indoors - but the majority of cats can - like 99% of all cats. I have seven, and they NEVER go outside - and three used to be outdoor only cats. They don't even ask because I don't make it an option. They don't act anything like a normal cat, because I never gave them the option to.
I just can't understand how people will still let their cats out even after losing five or six to horrid deaths. Heck, even having one cat hit by a car or torn apart by a wild animal should make people sick to their stomachs when even THINKING about touching a door handle to let a cat out. It's not normal. It's not natural. It's not "just what happens" when you have a cat. It should be a punishable offence by law. Dogs aren't allowed off leashes - why the heck should cats be any different?
Mine cats come when called, they follow me around, sleep with me every night, and act in every way like a dog - because I've never thought about them as being "just cats". Try seeing them like dogs, and then maybe people will start treating them the way they should - like mans' best friend.
Just teeks me off something awful.