3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> The male body

The male body

The body of a man is less focused on the business of reproduction than that of a woman. Once he has produced his sperm, his part in the process of starting a new life is finished, and the woman takes over as she spends the next 38 weeks with the baby growing and developing inside her. However, it is just as important for him to live healthily in the months before conception as it is for her.

The male reproductive system

This system is by no means simple and it is brilliantly designed to maximize the chances of impregnating a woman. Unlike a woman and her eggs, a man does not have a store of sperm when he is born.

Scrotal sac

This is the bag of skin that contains and protects the testes. It holds them outside the body where temperatures are slightly cooler. Sperm are made in the testes (singular: testis), or testicles, and are constantly being replenished. Sperm production begins at puberty and continues until very late in life, although it starts to slow down in late middle age. It takes about 70-80 days to produce a mature sperm, ready for ejaculation. Of the hundreds of million sperm in any one ejaculation, only a couple of thousand survive the journey into the uterus and on to the Fallopian tube.


Healthy sperm can swim towards an egg at speeds of 2-3 mm a minute. Only a few hundred will reach the egg and only one of those will penetrate the outer layers of the egg to fertilize it.

Male reproductive organs

The scrotum is held outside the body in order to maximize sperm production, which is at its highest when the testes are about 1°C cooler than the core body temperature


Each sperm is about 0.05 mm long and consists of three parts: a head, which contains all the genetic information; a middle piece, which provides the energy for the sperm to propel itself along, and a tail, which swishes from side to side as the sperm swims towards the egg.


The sperm mature in this part of the testis.

Vas deferens

When the sperm are mature, they pass along the vas deferens (sperm ducts) from the epididymis to the seminal vesicles.

Seminal vesicles

Sperm are stored here until a man ejaculates. The sperm mix with fluid made in the seminal vesicle, and other fluids from the prostate gland, to form semen, which is projected along the urethra.


During ejaculation, contractions at the base of the penis force semen along this tube, which runs all the way from the bladder, through the prostate gland and along the penis to its tip.

When a man ejaculates, semen containing sperm is projected from the seminal vesicle, along the urethra and out of the penis. In each ejaculation, between 2 and 6 ml of semen are released, each millilitre of which contains between 35 million and 200 million sperm. Not all of these are normal, healthy sperm - about a quarter of them cannot swim and have no chance of making it to the egg.