Only you can make a difference by spaying or neutering your pet. He won't have kittens. Your male cat can father up to 300 kittens in one year. Unneutered male cats tend to roam, get in fights and spray their smelly urine everywhere. In the long run spay or neuter surgery is less expensive than caring for unwanted litters.
Unaltered animals have more health problems than pets that have been spayed or neutered.
NO, NO, NO, Only pets that are over fed and under exercised get fat and lazy. An altered animal is more affectionate toward your family and less likely to run away. If your dog is neutered he will focus on your home instead of searching for females. When a cat is in heat she yowls, paces, screams, and tries very hard to get out. She will be very unhappy and so will you.