Neutered pets can't develop testicular tumors, the second most common malignancy in males, and have a lower incidence of prostate cancer, which is better for your pet and means lower medical bills. Spayed females typically stay healthier and live longer. They have a lower incidence of mammary tumors and no uterine or ovarian cancers, which is better for your pet and means lower medical bills. Sterilization does not change the pet's personality or cause weight gain. Removing the urge to mate focuses more of a pet's attention on the caregiver, aiding in training.
Sterilized pets behave better.
That's why pets should be spayed or neutered by age 6 months. Older pets can safely be sterilized as well. This routine surgical procedure removes the reproductive organs. It does not cause the pet pain or stress, and most pets recover within a day. Every litter matters.