Causes of infertility in men

About 40 percent of infertility cases involve issues with the male partner, either as the sole cause or a contributing factor. Male-factor infertility usually has to do with the quantity and quality of sperm in a man’s semen. Listed below are some of the more common conditions that can negatively impact fertility in men.


Anatomical Causes

After sperm are produced in a man’s testicles, they travel through small tubes to mix with semen before being ejaculated from the penis. If something in a man’s anatomy blocks the flow of sperm to the semen, it may result in low sperm count or poor sperm quality, making it more difficult for pregnancy to occur.

One of the more common anatomical causes of male infertility is a varicocele, which is an enlarged vein within the scrotum. It is thought that the enlargement can impede blood flow and raise the temperature within the scrotum, causing reduced sperm production and poorer sperm quality.

Varicoceles are very common and do not always cause infertility in men. It is estimated that about 15 percent of the male population have varicoceles (including Dr. Parry – so men who have one are not alone).

Other physical defects contributing to male infertility include testicular torsion (twisting and swelling of a testicle which may cause permanent damage), retrograde ejaculation, undescended testicle, and damage or blockage in the ducts that carry sperm to the semen.


Erectile Dysfunction (Impotence)

Erectile dysfunction, or impotence, is when a man is unable to get or maintain an erection for intercourse. This can be due to underlying disorders such as diabetes or heart disease but may also occur due to psychological issues including depression and anxiety. Lifestyle factors such as drug and alcohol abuse can also affect a man’s ability to obtain and sustain an erection. 

Hormonal Disorders

The production of healthy sperm requires a proper balance of sex hormones in a man’s body. Disorders affecting the thyroid and pituitary glands, for example, can negatively impact the amount of testosterone and other reproductive hormones in a man’s body. This can in turn have a negative impact on sperm production.


Lifestyle and Environmental Factors

Unhealthy lifestyle habits have been shown to negatively impact male fertility. Fertility experts also theorize that activities that increase the temperature of the scrotum, such as prolonged sitting, wearing tight pants or underpants, using a laptop computer and saunas and hot tubs, may decrease sperm production. Other lifestyle and environmental factors that can affect male fertility include:

  • Poor diet
  • Obesity
  • Smoking
  • Drugs & alcohol
  • Excessive stress
  • Exposure to environmental toxins such as industrial chemicals, lead or radiation.

Related Information: Fertility Testing for Men