On animal overpopulation...

Spaying or neutering plays an important part in controlling animal overpopulation. As a consequence there will be less euthanization of animals. In a practical sense, this will also cost the taxpayers less money. It costs money to capture, impound and later put these animals to sleep; this costs billions of dollars each year, according to the American Veterinary Medical Association.
As an animal lover, spaying/neutering animals shows responsibility in the owner’s part. Why run the risk of having an animal in heat roam the streets and getting hit by a car or having an accident, or contracting diseases?
Spaying or neutering also reduces the risk of certain types of cancers in some animals, the number of unwanted offspring, eliminates heat cycles for females and aggressive behavior in males. According to Spay USA (a great source for spay/neuter info), dogs and cats live longer lives after the procedure, which in the end is what any loving owner wants!