In the normal male reproductive tract, mature sperm are stored in the epididymides. They travel through the vas deferns into the urethra, and exit the penis during ejaculation. Vasectomy is a surgical contraceptive procedure whereby the vas deferens are permanently divided, preventing the spermatozoa from leaving the epididymis. Following vasectomy, a man can only ejaculate seminal fluids that are free of sperm cells.