Common causes of male infertility

Infertility is far from being a female only problem. As a general rule, in about one-third of cases, infertility is due to a cause involving only the male partner, in another one-third of cases, infertility is due to causes involving both the male and female and in the remaining one-third of cases, infertility is due to a cause involving only the female partner.

There are many causes of male infertility. It is usually caused by producing lower than normal levels of sperm or no sperm; having a blockage in the reproductive tract; abnormalities in the morphology (structure) of the sperm or in the motility of the sperm.

 These can be divided into three types:

  • Those a man is born with (congenital)
  • Those he develops throughout his life (acquired)
  • Other/unknown causes
Causes of infertility or subfertility include the following:


A low sperm count or absence of sperm in semen may indicate a problem with the Y chromosome, in particular Y chromosome micro deletion. Other genetic conditions include Klinefelter syndrome and Kallmann syndrome.


Cryptorchidism is a condition where one or both of the testicles are not found in the scrotum, but instead lie in the abdomen. It is also known as an ‘undescended testicle’. Some men may also be born without testicles, a condition called ‘anorchia’.

Congenital absence of vas deferens

This is a condition where the sperm ducts of a male do not develop properly. Sperm is not carried from the testicles to become part of semen, resulting in azoospermia. It is linked with cystic fibrosis.



Use of illegal drugs, alcohol, smoking and being overweight or obese are all risk factors for reduced fertility.

Sexual Dysfunction

Many men experience erectile dysfunction. This means they are unable to attain an erection and cannot have sex. Other men experience problems with ejaculation.


Men who previously had a vasectomy (an operation to make him sterile and prevent pregnancy) will experience what is called obstructive azoospermia.


A varicocoele is a swollen vein on a man’s scrotum.


History of a sexually transmitted infection, mumps or inflammation of the testicles may cause infertility.


Chronic disease such as diabetes and high blood pressure, exposure to radiation, high temperatures, and treatment with chemotherapy are all linked with infertility.