I am a strong supporter of spaying and neutering. I did a lot of research on it for a speech final last semester, and it's amazing how many myths there are that prevent some people from spaying. I tried to dispel these myths in my speech, and speak to people when I can about the benefits of altering their pets. My two female cats are scheduled to be spayed on May 20th. I find one of the hardest animals to convince people needs neutering is the domestic rabbit.
Males are less prone to cancer, but neutering helps with litter training, aggression, and stress.
Best of all, if you get your rabbits neutered, you can find a friend for them. Rabbits benefit a lot from companions, but they are too territorial to bond successfully if intact. Used under License.