Spaying and neutering are surgical procedures used to sterilize pets, but they differ based on the pet's sex. Spaying refers to the removal of a female animal's ovaries and usually the uterus, preventing pregnancy and eliminating heat cycles. Neutering, on the other hand, is the removal of a male animal's testicles, which stops the production of sperm and reduces testosterone levels. Both procedures help control pet overpopulation, enhance health by reducing the risk of certain cancers, and promote better behavior by lessening the desire to roam and mark territory.