For the vast majority of American dog owners, the question is a no-brainer: unless you breed dogs or participate in dog shows—or don’t mind being persona non grata at the dog park—you have your dog “fixed.” About 80 percent of U.S. dogs have been altered—relieved of their sex hormone-producing organs, a.k.a. gonads (testicles for males, ovaries for females), through a surgical procedure known as a gonadectomy (castration for the boys, spaying for the girls).
Of course, the primary objective of surgical sterilization is to prevent unwanted litters, and in that regard, the procedure is extremely effective. It became standard practice in the U.S. in the 1970s and has had a huge impact on the numbers of puppies roaming the streets or filling shelters. Animal welfare organizations continue to endorse it as the best and only way to get—and keep—shelter numbers down, even as many advocates also push for more research into alternative methods of contraception.