The testicles

The testicles are two small, oval-shaped organs, contained in a sac of skin called the scrotum. They hang below the penis. The testicles are sometimes called the testes. They are the main organs of the male reproductive system. From puberty, the collecting tubules inside the testicles produce sperm. The sperm can fertilise a female egg to make a baby.


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Sperm travels from the tubules to a coiled tube called the epididymis. This feels like a soft swelling at the back of the testicle. The epididymis widens to become the spermatic cord (vas deferens). This joins to a shorter tube called the ejaculatory duct. The ejaculatory duct connects to the urethra. This is the tube from the bladder to the end of the penis.

Sperm mixes with fluid from the prostate and seminal vesicles (glands that sit just under the bladder) before it is forced (ejaculated) along the urethra and out from the penis. The ejaculated fluid and sperm are called semen.

Male reproductive organs
Male reproductive organs

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The testicles also produce the hormone testosterone. Hormones are chemical messengers that help to control different activities in our bodies. Testosterone helps with:

  • your sex drive (libido)
  • getting an erection
  • having a deep voice
  • facial and body hair
  • muscle development.

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Back to Understanding testicular cancer

What is cancer?

Cancer is a disease of our cells. Sometimes cells go wrong and become abnormal. They keep dividing to make more abnormal cells which form a lump or tumour.

The lymphatic system

The lymphatic system includes lymph nodes (glands). Sometimes, cancer cells spread to lymph nodes near to where the cancer started.

What is testicular cancer?

Testicular cancer is more common in younger to middle-aged men. There are two main types – seminoma and non-seminoma.

Testicular self-examination

Regularly checking your testicles from puberty can help find a testicular cancer earlier, when it is easier to treat.