What is the purpose of spaying or neutering a dog?

The story behind the answer

Spaying (removing the ovaries ± uterus) or neutering (removing the testicles) prevents reproduction and lowers hormone-driven health risks. Females are protected from life‑threatening uterine infections (pyometra) and their risk of mammary tumors drops most if spayed before the first heat. Males avoid testicular cancer entirely and have reduced prostate problems. It can also decrease roaming, urine marking, and mounting, but it’s not a guaranteed fix for aggression—training and socialization still matter.

Beyond individual health, sterilization helps control pet overpopulation and reduces shelter crowding. Remember it with SNIP: Stop New pups, Improve health, Population control.