You should have your female kitten spayed or your male kitten neutered around six months of age. Spaying or neutering can:

• Help keep your cat healthy by eliminating many infections and cancers of the reproductive tract that can occur later in life.
• Eliminate howling during seasonal heats in females.
• Eliminate roaming and spraying. Un-neutered male cats often need to roam and get into fights with other males. This can be costly for owners, since bite wounds can become infected and require treatment from a vet.
• Keep unwanted animals out of shelters. Spaying or neutering your pet is cheaper than raising a litter of kittens, but it also ensures that your cat does not add to the millions of cats in shelters who are awaiting homes, or the millions more who are put down each year. The massive overabundance of pets is due to nothing more than human irresponsibility.