This Page is Quoted Directly From The Humane Society of the United States:
Spaying or neutering your pet is an important decision for pet owners. As animal lovers who value our pets, it is important to understand the impact of this decision.
It happens everywhere
In every community, in every state, there are homeless animals. In the U.S. as a whole, there are an estimated 6-8 million homeless animals entering animal shelters every year. About half of these animals are adopted, and tragically, the other half are euthanized. These are healthy, sweet pets who would have made great companions.
The number of homeless animals varies by state—in some states there are as many as 300,000 homeless animals euthanized in animal shelters every year. These are not the offspring of homeless “street” animals—these are the puppies and kittens of cherished family pets and even purebreds.
Yes, your pet’s offspring could be shelter animals
Many people believe that their pet’s puppies or kittens would never become homeless shelter animals. But the reality is that every time the dog finds his way under the fence to visit the neighbor’s female dog, or the indoor/outdoor cat comes back home pregnant again, the result is a litter of dogs or cats. Even if they are placed into homes, it is still possible for them to end up in shelters once they become “hard to handle,” or for them to reproduce further and for the next generation of puppies or kittens to wind up homeless.
Many people are surprised to learn that nationwide more than 3 million cats and dogs are euthanized in shelters. Spay/neuter is the only permanent, 100-percent effective method of birth control for dogs and cats.