Removal of the ovaries and uterus Ideal age is 4 to 6 months. If spayed before the first heat cycle, your pet has a less than 1 percent chance of developing breast cancer.

If spayed after one heat cycle, your pet has an 8 percent chance of developing breast cancer.

If spayed after two heat cycles, the risk increases to 26 percent chance.

After two years, no protective benefit exists.

Removal of the testicles and spermatic cord. Ideal age is 4 to 6 months.

Eliminates the risk of testicular cancer, the second most common tumor in male dogs.

Greatly reduces the risk of prostate cancer and prostatitis.

Reduces the risk of perianal tumors.

Reduces roaming and fighting.

Eliminates or reduces spraying or marking in males neutered before 6 months of age or before the onset of these behaviors.

Eliminates the risk and spread of sexually transmitted diseases.

Eliminates unwanted litters.

More thank 4 million pets are euthanized in U.S. animal shelters each year simply because they have no home. Many are puppies and kittens less than 6 months old.