As far as I've ever known... there's no reason NOT to spay and neuter your animals and there are a millions of reasons why you should.
Those millions of reasons are the millions of animals that are put to sleep every year in shelters simply because there are not enough homes for them to go to.
Perfectly normal, happy, healthy animals die because people still don't realize it's their responsibility as a pet owner to spay and neuter their animals.

I adopted Buddy when he was already a year old, I took him to be neutered a few months later and he never even noticed anything was missing, I'm sure Bear will be the same.