Fertility problems - Getting pregnant: the man

Fertility problems

Getting pregnant: the man's role

This diagram shows the parts of the man's body involved in making sperm.

Source:
Meniru GI.
The male reproductive system.
In: Cambridge guide to infertility management and assisted reproduction. Cambridge University Press, Cambridge, UK; 2001.

Your testicles make sperm. They sit under your penis in a bag called the scrotum.
A series of narrow tubes take the sperm from your testicles toward your penis.
Two sex glands add fluid to your sperm as they pass through the tubes. The fluid gives sperm energy and helps them to swim. The mixture of sperm and fluid is called semen.
When you

ejaculation
When a man ejaculates, his penis suddenly releases semen, the white or transparent fluid that carries sperm.

ejaculate, your penis pushes out the semen.
Your urethra is a tube that carries both urine and semen out through your penis.

See More about sperm.

Your testicles

Your testicles make sperm and sex hormones.

Sperm grow and are stored in coiled tubes.

Testicles make up to 120 million sperm each day. The sperm become full-grown in about 10 weeks to 12 weeks.

Your testicles lie inside a pouch of skin called the scrotum. This hangs down outside your body because sperm grow best when the temperature is a few degrees lower than your

body temperature
Your body temperature is a measure of how warm you are. If you have a higher temperature than normal, it can mean that your body has an infection or you have a fever. Women also have a higher temperature at the time of month when their ovaries release an egg (ovulation).

body temperature.

When a male baby is growing in the womb, its testicles are inside its body. But as the baby grows, the testicles move downward. When the baby is born, the testicles are normally outside the body, in the scrotum. In some boys, the testicles stay inside the body. This can cause problems later, as a testicle left inside can't grow normally and can't make sperm.

Joined to each testicle is a tightly coiled tube (called the epididymis). Sperm are stored here once they have grown.

What happens when you ejaculate?

When you are sexually excited, the tubes in your testicles get narrower and squeeze sperm out. The sperm travel through a series of tubes toward your penis. The sex glands and the prostate add fluid to the sperm to make semen. The semen is pushed out of your penis through the urethra.

When you ejaculate, you normally release between 1.5 milliliters and 5 milliliters of semen.

Source:
American Urological Association
Report on optimal evaluation of the infertile male.
October 2001. Available at http://www.auanet.org/guidelines (accessed on 16 June 2008).

² That's about one teaspoonful or less.

Because your urethra carries both semen and urine out of the body, the neck of the bladder (the sac that holds urine) normally closes during ejaculation. This prevents semen from going into the bladder and it also stops urine from getting into semen.

Sources for the information on this page:

Meniru GI.The male reproductive system.In: Cambridge guide to infertility management and assisted reproduction. Cambridge University Press, Cambridge, UK; 2001.

American Urological AssociationReport on optimal evaluation of the infertile male.October 2001. Available at http://www.auanet.org/guidelines (accessed on 16 June 2008).

This information was last updated on Mar 06, 2009

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