Spaying or neutering your cat is an important decision that deserves careful consideration. Spaying means removing the reproductive organs (uterus and ovaries) of a female cat. 
Neutering is the male equivalent: removing the testicles of a male cat. Both surgical procedures are performed by veterinarians while your cat is under general anesthesia. Spaying or neutering your cat prevents your female cat from having kittens and prevents your male cat from impregnating females.
The most obvious argument in favor of spaying or neutering your cat is to help limit the number of unwanted cats in the world. According to the Humane Society of the United States (HSUS), there are an estimated 6 to 8 million cats and dogs entering animal shelters each year. Roughly half of these are adopted by new owners, leaving an estimated 3-4 million pets being euthanized each year. Spaying or neutering your cat helps prevent unwanted litters of cats from contributing to this problem.
One argument against spaying or neutering your cat is that some cat owners want their cats to reproduce, and feel confident they can find homes for all of the offspring. While this may be true, many cat owners find that it can be more difficult than they thought to find those homes. Choosing against spaying or neutering your cat also means you will have to deal with the kittens or puppies whenever they arrive, not on a schedule of your choosing. A female cat can have up to three litters a year, with each litter having an average of 4-6 kittens. Female cats can go into heat as young as only four or five months of age. That can be a lot of kittens to find homes for, perhaps sooner than you had imagined.
Spaying or neutering your cat has been shown to help your cat potentially live a longer and healthier life. In female cats, spaying eliminates the possibility of ovarian or uterine cancer, as well as significantly reduces the rate of breast cancer. In male cats, neutering eliminates the chance of testicular cancer and also reduces prostate cancer rates.
Spaying or neutering your cat can also make life better for you, since it often eliminates some behavioral problems in cats. Male cats often mark their territory by spraying; neutering often eliminates this behavior. Female cats who are spayed do not go into heat. When cats are in heat they tend to whine and cry a great deal, and spend a lot of time tying to escape from the house to find males to mate with.
Spaying or neutering your cat is a one-time surgical procedure that can help reduce the number of unwanted cats in our world. For those of us who love animals, it is hard to imagine that there are already so many unwanted cats, but the statistics are grim. Spaying or neutering your cat can also help your cat live a longer and healthier life.
