Please, don't get kitties spayed so young. Five months is a good, healthy age to do it.

Spaying too young CAN endanger a kitten's life. I saw a case at my vet's office where the kitten was spayed at 3 months, and she nearly died. She was too young for the anesthesia, and too weak to recover well from the surgery. She survived, but it was a close thing.

Talk to your vet first, and wait until at LEAST after four months to have your little lady spayed. I don't know about males, considering there is a non-invasive surgery, but please be careful with your females.