Quote Originally Posted by boscibo
Definitely do not let your unneutered males out! They can father kittens at a very young age and are much more apt to get into fights (requiring big vet bills) than neutered males.
Don't forget the unspayed females! You DO NOT want to have to deal with taking care of and vet bills for a pregnant mother and then her kittens! And the associated health risks, of course.

The option is completely up to you. I would personally never let mine wander outside because I would be too afraid of him getting run over, or stolen by a neighbor, or attacked by a coyote or... well toooooo many bad thoughts run through my head so I keep him very close by!!