Vasectomy is the surgical division of the vas deferens. Vasectomy prevents sperm from being released into semen during ejaculation, thus preventing pregnancy. Vasectomy may be recommended for adult men who are certain that they wish to prevent future pregnancies (permanent sterilization). Vasectomy is not recommended as a temporary or reversible procedure. Vasectomy is usually done in the surgeon's office while the patient is awake but pain-free (using local anesthesia). A small incision is made in the upper part of the scrotum, under the penis.