Vasectomy is a simple, safe procedure that makes a man sterile (unable to father a child). It is the most effective birth control method for men.

Your Reproductive System

For pregnancy to occur, a man's sperm (male reproductive cells) must join with a woman's egg. To understand how a vasectomy works, you need to know how sperm are produced, stored, and released by the body.

• The urethra is the tube in the center of the penis. It transports both urine and semen. When you have an orgasm, semen is ejaculated out of the urethra.

• The seminal vesicles and the prostate gland secrete fluids called semen. This sticky, white fluid helps nourish sperm and carry them along.

• The epididymis is a coiled tube that holds the sperm while they mature.

• The scrotum is a pouch of skin that contains the testes.

• The testes are glands that produce sperm and male hormones.

• The vas deferens are tubes that carry the sperm from the epididymis to the penis.

• Sperm (shown magnified) carry genetic material.