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Male Fertility Issues

What Is Male Infertility?

According to, approximately one-third of infertile couples have problems with male infertility. Male infertility usually occurs when men produce damaged or insufficient amounts of sperm. It can also be caused by blockages that keep sperm from being ejaculated.

What Are the Risk Factors for Male Infertility?

There are a variety of risk factors for male infertility. They include:

  • age over 35
  • smoking
  • heavy alcohol use
  • use of certain illicit drugs, such as anabolic steroids
  • bicycling for long periods, especially on a hard saddle
  • being overweight or underweight
  • a history of sexually transmitted infections (STIs)
  • toxin exposure
  • testicles that are kept too warm
  • prior vasectomy or reversal
  • inherited fertility disorders
  • some medical conditions, including Celiac disease (an autoimmune digestive disease), genetic chromosome defects, and certain cancers
  • certain medical treatments, such as chemotherapy and radiation

Sperm Disorders & Male Infertility

Sperm problems are a major cause of infertility in men. These disorders include: 

  • low sperm count, i.e. too few or no sperm in the semen
  • low sperm motility, i.e. sperm that don’t move as well as they should
  • malformation of the sperm

A number of factors can affect sperm production.


Varicocele is a common cause of male infertility. Men with this condition have enlarged veins around the vas deferens. The vas deferens are the ducts that carry sperm from the testicles to the urethra.  

Varicocele causes blood to pool around the testicles. This makes the temperature inside the scrotum increase. Heat can lower sperm production.


Infections can interfere with sperm production, health, and movement. They can also cause scarring that blocks the passage of sperm.

Infections that can affect fertility include:

  • sexually transmitted infections (STIs)
  • prostatitis, an inflamed prostate
  • mumps, which can cause an inflammation of the testicles known as mumps orchitis
  • urinary infections


Certain medications can affect sperm production and impair fertility. These include:

  • testosterone replacement therapy
  • anabolic steroid use
  • chemotherapy
  • certain antibiotics
  • some ulcer drugs (i.e. H2 blockers)

Undescended Testicles

This condition occurs when one or both testicles do not descend from the abdomen during fetal development. It can interfere with sperm production and movement.

Hormone Imbalances

Hormonal imbalances can affect sperm growth and maturation. They can also prevent the release of sperm and affect sex drive.

Hormonal problems may begin in the brain or the testicles. Glands in the brain control hormone production.  However, most hormones related to sperm production are made in the testicles.

Other Causes of Male Infertility

A number of other factors are also associated with male infertility, including:

Genetic Conditions

Certain genetic conditions can affect fertility. For example, men with cystic fibrosis may be born without sperm ducts. Chromosomal diseases can also affect development of the male reproductive tract.

Previous Injuries

Injuries can cause scarring in the sperm ducts that carry sperm from the testicles. One cause of such scarring is extended bicycle riding.

Retrograde Ejaculation

Men with retrograde ejaculation ejaculate backward into their bladders. This condition makes conceiving difficult. Retrograde ejaculation can be caused by a variety of things, including:

  • previous surgeries
  • diabetes
  • spinal injuries
  • certain medications, particularly those prescribed for enlarged prostate

Spinal cord injuries can also cause a complete lack of ejaculation. However, men may still make sperm, even if they do not ejaculate it.

Sexual Intercourse Problems

Concerns about infertility can cause sexual problems within couples. However, sexual problems can also contribute to infertility by reducing opportunities to conceive. Such problems include:

  • erectile dysfunction
  • premature ejaculation
  • painful intercourse
  • emotional or psychological problems that interfere with sex

Environmental and Lifestyle Causes

Infertility in men may also have environmental or lifestyle causes, including:

  • heavy metal exposure
  • exposure to pesticides
  • tobacco use
  • alcohol use
  • cocaine and marijuana use
  • obesity
  • overheating of the testicles

Behaviors that can increase the temperature of the testicles include:

  • frequent use of hot tubs or saunas
  • using a laptop computer on your lap

Working with your laptop on a desk or support can reduce the amount of heat on your testicles. This may be a simple way for some men to improve their fertility. 

Content licensed from:

Written by: the Healthline Editorial Team
Medically reviewed on: Jul 22, 2014: Kenneth R. Hirsch, MD

This feature is for informational purposes only and should not be used to replace the care and information received from your health care provider. Please consult a health care professional with any health concerns you may have.
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