There are several issues associated with this topic. First, is it safe? Do kittens have problems with the anesthetics? Do they recover okay? Does early neutering affect a kitten's health or growth?
Let me address these questions now.
Second, do they have problems with the anesthetics? Young kittens do very well with the anesthetics when giving appropriately.
Do they recover okay? The younger pets actually recover earlier. Most kittens will be active and even playing within a few hours after their surgery. Older pets take longer to recover.
How does this affect the pet population? It actually affects it in a good way. Many cats adopted from shelters are not neutered as they should be. Many of these cats go on to reproduce and send more pets to the shelter, many of which are ultimately euthanized.
Does early neutering affect their health or growth? Many veterinarians have worried that early neutering would affect a cats growth, future obesity, and overall health. Research has found that most of these concerns are unfounded. The growth, a cat's weight and overall health were very similar in cats neutered early vs. neutered at a traditional age.