Kittens are able to be neutered as early as 6 weeks of age, according to Cat Channel. Known as early-age or pediatric neutering, the procedure is possible on kittens who weigh at least two pounds.
Both the American Veterinary Medical Association and the American Association of Feline Practitioners endorse pediatric neutering, reports Becky Robinson of Alley Cat Allies for Cat Channel. It is a measure used to prevent unwanted litters, particularly when female litter mates are present, as kittens are able to conceive as early as four months of age. No adverse effects or long-term side effects related to early-age neutering have been reported, Robinson says.