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About the Testes

The testes, or testicles are a pair of oval organs in men that produce sperm and the male hormone testosterone. The testes are located in the scrotum, the sac that hangs below the base of the penis.

When a boy reaches puberty, special coiled tubes inside his testes begin to make sperm. From this point on, the boy’s testes continue producing sperm for the rest of his life, at the rate of hundreds of millions each day.

The testes also produce and release testosterone. This hormone is a major part of puberty in boys. As a boy goes through puberty, his testes produce more and more testosterone, which causes him to develop a deeper voice, bigger muscles, and body and facial hair, among other things.

Normal Puberty in the Boy
At some point, usually after a boy’s 10th birthday, puberty begins when the hypothalamus releases gonadotropin-releasing hormone (GnRH). When GnRH reaches his pituitary gland, it stimulates the pituitary to release two more hormones—luteinizing hormone (LH) and follicle-stimulating hormone (FSH).

These hormones (LH and FSH) go to the testes and give the signal to start sperm production. They also trigger the production of the male sex hormone—testosterone. This hormone is then responsible for the characteristic changes that a boy goes through during puberty. These changes include:

  • Body Shape—the boy gets taller and his shoulders get broader. He also gains a lot of weight, much of it due to an increase in the size of his muscles.
  • Breasts—many boys experience swelling under their nipples—this is known as gynecomastia, and is temporary.
  • Voice—the voice gets deeper.
  • Hair—hair appears under the arms, on the legs and face, and above the penis. Chest hair may appear during puberty or years after, although not all men develop chest hair.
  • Skin—the skin may get oilier and the boy may sweat more. In addition, acne may develop and is normal during this time when hormone levels are high.
  • Penis and Testicles—the penis and testes get larger. The boy may have erections more often due to an increase in sex hormones. He will also begin to produce sperm during puberty and will start to experience ejaculation.
Adrenal Hyperplasia, Congenital
Froelich's Syndrome
Germ Cell Tumors, Extracranial
Germ Cell Tumors, Testicular
Kallmann Syndrome
Klinefelter's Syndrome
Laurence Moon Syndrome
McCune Albright Syndrome
Noonan Syndrome
Prader Willi Syndrome
Precocious Puberty
Undescended Testicle
  There are other rare conditions of the testes. To find more information about some of these conditions, use the section of this site called Rare Diseases A to Z.

If your child has been diagnosed with a condition of his testes, the doctor may recommend one or more of the following tests. For other tests and diagnostic procedures use the section of this site called Medical Tests A to Z.
CT Scan of the Head and Face
Follicle-Stimulating Hormone
Genetic Testing
Human Chorionic Gonadotropin (hCG)
Luteinizing Hormone
Magnetic Resonance Imaging (MRI) of the Head
Thyroid Hormone Tests
Thyroid-Stimulating Hormone (TSH)


This listing provides you with Internet sites that are sponsored by government agencies or are well-known and credible national organizations.

» Go to the Testes Resource Directory


Last modified on: 30 June 2015