Unless you want a houseful of kittens or puppies, it’s best to get your cat or dog spayed or neutered early in life. Typically this is done between 5 and 8 months of age, those there are some studies suggesting that you should wait until your pet is a year old. (Then there are other studies saying that that causes OTHER problems…so as always, it’s best to check with your vet.)
Spaying removes the uterus and both ovaries from female cats and dogs. Neutering removes the testicles from male cats and dogs. Though both obviously have the desired effect of stopping any chance of reproduction for you animal, they also have other positive outcomes. Females who are spayed won’t go into heat each month, which means they also won’t try to escape your house or yard in search of a mate. Likewise, males who are neutered won’t be affected by females in heat and therefore won’t be as hard to control and won’t have the tendency to roam that un-neutered males have.
In addition to behavioral changes spaying eliminates the risk of uterine or ovarian cancer for your pets; neutering eliminates the risk of testicular cancer. Both decrease the risks of other cancers like mammary or prostate cancer. Not spaying your cat on the other hand can cause her to develop urinary problems like pyometra and in general not spaying or neutering your pet can lead to unwanted pregnancies, lost pets and even cancerous tumors later on.
Talk to your vet to see when the time is right to spay or neuter your pet.