On average, female cats produce one to two litters of four to six kittens per year, according to the ASPCA. Female dogs produce, on average, one litter of four to six puppies per year. While almost everyone enjoys kittens and puppies in general, there are fewer loving homes than homeless dogs and cats in America. In fact, five to seven million enter animal shelters each year. Of these former pets and strays, shelters euthanize three to four million. As anyone who has ever watched Bob Barker on The Price is Right knows, spaying and neutering your dogs and cats will help control America's pet population. However, what some may not know is that it can also prevent serious health issues.