littermates, one neutered

Question
Hi Dr. Connell, I have two 14-wk-old littermate kittens, one male, one female.  I got the male neutered recently, wanting to wait until the female is a little older/bigger.  Since he came back from the vet, she is hissing and threatening to him.  Does he smell different or something?  They usually play/wrestle/nap together 75% of the time.  He seems cowed and confused.  Is this typical?  Will it even out?  Thank you... Mary

Answer
Hi Mary,
Just to set the record straight I am not a vet. My profile states that I am a registered vet tech.
I really hate to see male cats neutered so young, they are barely developed at that age! Males should be neutered around 6-7 months and females from 4-7 months of age. Their bone structure doesn't finish forming in the male until around 7 months old. She is old enough to spay right now, unless she is really tiny. I know that your vet told you this was good to do him at such a young age but I am not sure I agree with the consensus out there. Most older vets don't also. But that is neither here nor there.

He is done and what is happening is very common and will stop in a few days. Yes, he smells like a strange place to her so she thinks he is a stranger.

Once the smell of the house is back on him she won't notice. The tables may be turned however, once she goes in and she smells strange to him!
But then again it will all even out. Bless you for getting them done no matter what!!