Obstructive causes of male infertility

The path of the sperm cells can be obstructed in several places:

  • In the testicles, where sperm cells are produced
  • In the epididymis, the tube that carries sperm from the testicle to the vas deferens
  • In the vas deferens, the tube that transports sperm to the prostate and posterior urethra

The most common causes of obstruction are infections (for example, gonorrhoea, chlamydia, prostatitis, tuberculosis), birth defects (congenital disorders), or trauma to the genitalia.

Treatment depends on the amount of obstruction. Semen can be collected by biopsy from the testicle or the epididymis. Surgery on the vas deferens can reestablish the pathway.

Cystic fibrosis

Cystic fibrosis (CF) is the most common genetic disorder in white persons, and a small number of white men have CF mutations. These men might lack the vas deferens on both sides. This means that sperm cells cannot mix with the ejaculate, so the ejaculate will not include any sperm (azoospermia). To achieve pregnancy, sperm must be collected directly from the testicles by a biopsy. In the case of CF as the cause of male infertility, the female partner should also be genetically tested for CF. Two carrier parents have a 50% chance of having a child with CF.


Vasectomy is a surgical procedure that disconnects the epididymis from the vas deferens to make the man infertile. This procedure is permanent and is considered to be irreversible. In some cases it can be reversed, but the chance of success depends on when the vasectomy has taken place.

Problems with ejaculation

In some cases, the ejaculate cannot reach the urethra. The man might not be able to ejaculate, it might be delayed, or the semen might go into the bladder (retrograde ejaculation). Causes can be psychological, physical (for example, nervous system dysfunction after surgery or trauma), or related to medication use. Treatment options include medication and physical stimulation.