Infertility: Problems With the Man's Reproductive System

The most common cause of male infertility is low sperm count. Absence of sperm in the semen is less common, affecting 1 out of 100 men and affecting 10 to 15 out of 100 infertile men.^{Reference 1}

Causes of sperm count problems include:

• Hormonal problems in the Reference testicles Opens New Window or Reference pituitary gland Opens New Window. The pituitary gland releases hormones that stimulate the testicles to produce Reference testosterone Opens New Window.
• Testicular injury or failure, either present at birth (congenital) or associated with radiation or toxic chemical exposure.
• Cancer treatment with certain kinds of chemotherapy or radiation.
• Reference Antibodies Opens New Window that attack sperm and that also may be present in semen. Sperm antibodies sometimes develop when a man's sperm has been exposed to his immune system (outside of the testicles). This may happen after a vasectomy, an infection, or an injury to the testicles.^{Reference 2}
• Drug use (some prescription medicines, and marijuana and tobacco use).
• Structural problems. These include:
  • A Reference varicocele Opens New Window in the testicles.
  • Blocked ejaculation due to a surgical Reference vasectomy Opens New Window.
  • Absence of a Reference vas deferens Opens New Window (a birth defect that may be associated with the Reference cystic fibrosis Opens New Window genes).
  • Retrograde ejaculation (the ejaculation of semen into the bladder rather than out through the penis).
• Chromosomal problems (such as Reference Klinefelter syndrome Opens New Window).
• Genetic problems.

See a picture of the Reference male reproductive system Opens New Window Reference Opens New Window.

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