Vasectomies generally are performed in a clinic or in a doctor's office. Usually there is a counseling session, and some practitioners prefer that the wife attends.

The procedure, as detailed in the Public Health Service booklet, "A Male Sterilization Procedure," is as follows:

With the man lying down, the doctor locates on one sie of the scrotum the vas deferens tube that carries sperm to the penis.

An anesthetic is injected. "The man will feel a little pain like a pin prick from the needle."

When the area is numb, the doctor uses a clamp to hold the vas and then makes an incision in the scrotum.

A small loop of the vas is pulled out and a small section removed surgically. The two ends of the vas are then tied off and the scrotum incision stitched.

The procedure is repeated for the second vas tube.

After the operation, patients are told to keep off their feet as much as possible for the first day and avoid strenuous activity for about a week. Sex may resume, says Preterm, usually in four or five days.

Birth-control methods must continue to be used six to eight weeks until sperm left in the vas deferens is cleared. Semen is checked for sperm in a follow-up appointment.