It is used as a means of contraception in many parts of the world. In comparison, about 15 percent of couples rely on female sterilization for birth control. Approximately half a million vasectomies are performed in the United States each year. About one out of six men over age 35 has been vasectomized, the prevalence increasing along with education and income. Among married couples in this country, only female sterilization and oral contraception are relied upon more often for family planning.
Vasectomy involves blocking the tubes through which sperm pass into the semen.
Sperm are produced in a man's testis and stored in an adjacent structure known as the epididymis. During sexual climax, the sperm move from the epididymis through a tube called the vas deferens and mix with other components of semen to form the ejaculate. All vasectomy techniques involve cutting or otherwise blocking both the left and right vas deferens, so the man's ejaculate will no longer contain sperm, and he will not be able to make a woman pregnant. In the conventional approach, a physician makes one or two small incisions, or cuts, in the skin of the scrotum, which has been number with a local anesthetic. The vas is cut, and a small piece may be removed.