There are dozens of urban legends and senseless rumors about the effects of castration in dogs and cats. Most of these rumors and legends, if not all, are false.
The only reason to not neuter a dog or cat is that we want them to reproduce.
You just have to go through an animal shelter to see the hundreds of animals that need home.
Benefits of neutering a male:
• Neutered dogs and cats are less territorial and dominant, a great benefit for them and for you.
• Their behavior will be less aggressive, especially when they are with other males as they will not fight to be dominant.
• The dog or cat will have less desire to escape (especially when the females are in heat, when usually they escape).
• Neutering very significantly reduces the chance of developing tumors and infections in testicles, penis and prostate.
• Our animal will have better health, as their defenses will not weaken as a result of stress with females in heat.
• We will have a quieter and less nervous animal.