Most of the information below is copied from the Cat Fanciers Assocation Website. Please check with your veterinarian to find out what procedure he/she is most comfortable with and recommends
Unfortunately, there is debate among veterinarians about the correct age. Waiting too long (1 year) to spay/neuter results in problems not easily overcome such as: territorial aggression, spraying (and other problems) so I will not include that option below.
The pros and cons of YOUNG vs "TEEN" given below and the study link below.
YOUNG AGE: (7-12 weeks)
pros: straightforward and uncomplicated. Kittens recover rapidly (faster than the 5-6month age) and are often up and playing 2 hours after surgery
cons: Many Veterinarians were not trained to perform surgery on infant kittens. Your veterinarian may feel more comfortable performing on the typical age kitten (5-6months). Many owners feel uncomfortable giving their “babies” surgery.
TYPICAL AGE: (5-6 months)
pros: Most Veterinarians have years of experience and feel very comfortable spaying/neutering a cat at this age.
cons: Possibly maturity has begun and undesirable behaviors have begun to develop in your teen cat: marking territory, breeding, aggression, heat cycles, territorial
Many breeders prefer to spay/neuter their kittens before they are placed with their new owners. I do not do that and you can choose the age for yourself. i hope this information helps you understand the options and the pro's & con's of each.
An interesting study reported on the CFA (Cat Fanciers Association) website if you are intersted to read: http://cfa.org/owners/catcare/spayneuter/earlyspayneuter.aspx