I personally don't think that cats should be outside. But it's a personal choice. I have some outdoor cats that I take care of. One came with the house, it belonged to the previous owner who died so my landlord asked that I put food out for it. I decided it would be better to leave her outside because she'd been an outside cat for 15 years and she never leaves my patio. And my roommates cat really doesn't like other cats, it wouldn't have been happy for anyone to have brought her indoors. But since I put food outside I have a few other cats that have decided to make my porch their home. I think if the kitten has only lived indoors you should keep it indoors because it's safer, and for many other reasons. But there are many people on this board who do let their cats go outside.. So I guess it just has to be a personal decision for you.