I volunteer for a feline rescue. We usually spay and neuter at 2 lbs. or around 8-10 weeks. If you wait until they are much older say 4-6 months you run the risk of the females going through a heat and getting pregnant. We have a lot of kittens having kittens and the males starting to mark their territory. Check with your local rescues for a nice discount and yes we have a qualified vet doing the spays and neuters.