Please do not breed your cat or allow it to breed, when i answered this question for you there were 10,6038 cats waiting to be adopted on petfinder alone, please see the listed link below http://www.petfinder.com/pet.cgi?action=3 A cat or dog will continue to come into heat as long as it is alive, as the animal becomes older the heat cycles become less and less regular, you female pets should be spayed and not spaying them can lead Mammary cancer is the third most common cancer in cats. Reproductive hormones are one of the primary causes of mammary cancer in the cat. Cats who have been spayed have a 40-60% lower risk of developing mammary cancer than those who have not been spayed. Tumors of the reproductive tract: Tumors also occur in the uterus and ovaries. An OHE would, of course, eliminate any possibility of this occurring. They are not commonly seen cancers in cats, but they do occur. Infections of the reproductive tract: Unspayed cats may develop a severe uterine disease called pyometra. With this disorder, bacteria enter the uterus and it becomes filled with pus. In addition cat that are older have a tendency to have kittens with medical problem and there is also a rick of the cat dying in labor, http://www.peteducation.com/article.cfm?cls=1&cat=1364&articleid=925 National Stats The sad fact is once a puppy is past its cuteness; or a dog displays behaviors we do not know how to deal with, many canines are discarded like old newspapers. On average 100,000 dogs and puppies are listed on http://www.petfinder.com/ daily. The National Council reports it on Pet Population Study and Policy, from the 5000 or so US agencies who responded to the survey, that over 2 million dogs enter shelters annually. Of those 27% are relinquished by owners, 42% are turned in by animal control, 31 by other sources, of these dogs, 56% are euthanized.it is sad because this is also true with cats, and kittens