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The Most Common Causes of Male Infertility

Updated: Nov 18, 2021

Common causes of infertility in males

It is generally expected that conceiving should come immediately when a sexually active couple decides they are ready for babies. Unfortunately, it doesn’t play out that way most of the time. Trying to get pregnant can take longer than expected which can be worrying and frustrating especially when it’s related to circumstances beyond your control.

One in seven couples in the United Kingdom have challenges with trying to conceive (NHS).

Most societies perceive infertility as a female issue and women will usually question themselves as the cause when trying to get pregnant proves difficult. The reality is different. The causes of infertility can be related to either member of the couple or a cause may not be identified.

Read on to understand the common causes of infertility in men.

Definition of Infertility

If a couple has not achieved a pregnancy after 12 months or more of regular unprotected sexual intercourse, they are living with infertility. One-third of infertility cases are due to factors related to the male e.g., sperm quality or quantity, one-third of cases are due to a mixture of male and female factors or are unexplained and one-third of causes are related to female factors alone.

The Human Fertilisation and Embryology Authority (HFEA) states,

“The most important thing you can do when making decisions about fertility treatment is to ensure you are well informed.”

This applies to any issue concerning your health; a healthy lifestyle and achieving better health begins with getting the right information about your health.

If it is taking longer than you hoped to get pregnant, it is important that you get the right information that will inform your decisions. Yes! getting trustworthy and relevant information is the most important self-care tip.

This post focuses mainly on the causes of infertility in males. Read about male fertility testing and ways to improve sperm quality in our previous article.

We will be posting about the causes of infertility in females and unexplained infertility in future blog posts.

The underlying cause of male infertility

For conception (the process of becoming pregnant) to happen:

  • Healthy sperm must be produced and developed in sufficient quantity.

  • The sperm must enter the female body (by sex and ejaculation) and move to meet the egg.

  • Along the way, the sperm undergo a maturation process which will allow them to fertilise the egg.

  • Once the sperm has reached the egg, they will try to enter so they can fuse with the egg (fertilisation). Only one sperm will be able to fully penetrate and fertilise the egg to create a zygote. The zygote will eventually become the baby.

A failure in one or more of these requirements results in conditions such as oligospermia (low sperm count), teratospermia (sperm have an abnormal shape), asthenospermia (reduced or poor motility of the sperm), and azoospermia (absence of sperm in the semen).

You can read more and watch a video about the process of conception in our article ‘Everything you need to know about fertility tests’.

Causes of Male Infertility

The Men’s Health Forum states that infertility affects 1 in 20 men. As a result of lifestyle changes, sperm count has generally fallen in recent years. It is also recorded that in the 1 of 20 men that are affected by infertility, 1 in 5 (20%) of them have low sperm count while 2-3 out of 100 men (2-3%) produce no sperm at all.

Generally, fertility for men begins to decline at age 40.

Find out more about the common causes of infertility in men below.

Lifestyle Habits that can affect fertility


Action on Smoking and Health shows that infertility is one of the health challenges traceable to smoking. It has also been said that inordinate or uncontrolled intake of tobacco hurts fertility.


Bodyweight has an interesting effect on fertility. A male with a BMI greater than 30 has a high chance of experiencing infertility as the higher the sperm count, the higher the probability of a low sperm count.

Being overweight can also lead to hormonal imbalances as well as an increase in the temperature of the scrotum which can damage the sperm.


It is recommended that not more than 14 units of alcohol should be ingested per week, a unit of alcohol equals half a pint of beer. An excessive intake of alcohol could reduce the chances of conception.


Intake of anabolic steroids and testosterone supplements are known to interfere with the hormones required to produce sperms.

Environmental exposure

Excess exposure to environmental agents is detrimental to the quality, production, or function of sperm. This includes overheating the testicles e.g., prolonged exposure to hot tubs and baths. Other agents such as industrial chemicals, heavy metals, radiations, and X-rays can also cause damage to the DNA structure of sperm.

Medical Causes of infertility

There are a variety of health conditions that can affect fertility and they include:


In this condition, enlarged veins are found just outside one or both sides of the testicles. They can be similar to varicose veins seen in the leg.

Varicocele may affect sperm count and quality. Your urologist may recommend surgery (which can also be done by keyhole surgery) method also or a procedure to block the blood flow to the varicocele. Treatment can help improve sperm count and quality.

Genetic Conditions

Conditions such as Klinefelter syndrome (a condition affecting the chromosomes in males who are born with an extra X chromosome) and Kallman’s syndrome (a rare genetic syndrome) can cause infertility.

These conditions affect the hormone levels from the brain, testes, thyroid or adrenal glands can affect sperm production and development.

Auto-immune causes: Anti-sperm antibodies

This occurs when your immune system perceives sperm as foreign harmful bodies and then produces antibodies that fight against the sperm. These antibodies are called Antisperm Antibodies. Treatment using intra-cytoplasmic sperm injection (see the last section) may be recommended.

Undiagnosed coeliac disease

Living with undiagnosed coeliac disease has been said to be a likely cause of infertility in men and women. It is recommended that couples with unexplained infertility should take blood tests to ascertain that coeliac disease is not the challenge.

How coeliac disease affects infertility is still unknown but there are a couple of theories, one of which is that coeliac disease affects an individual from absorbing nutrients that are essential for a healthy reproductive system.

Medication and treatments

Some medications and treatment options can also have an effect on fertility. For instance, a male who undergoes chemotherapy, a procedure for cancer patients stands a chance to have his sperm production permanently affected. Likewise, radiotherapy can lead to scar tissue which blocks the passage of sperm.

Also, some medications such as antidepressants, antipsychotics, and certain blood pressure medications like beta-blockers can affect libido and erectile dysfunction.

Treatments may include withdrawal of the drug and switching to an alternative drug. Sperm freezing can be done prior to chemotherapy or radiotherapy.


Sexually transmitted and non-sexually transmitted infections can cause reversible or permanent infertility. Infections may block the ability of sperms to travel from the testes to the penis. Infections such as orchitis (inflammation of the testicles) or epididymitis (inflammation of the epididymis behind the testicles), HIV, or gonorrhoea. Where appropriate antibiotic treatment will be given. Assistive reproductive treatments may be offered (see the last section).

Previous surgery

Permanent damage may be caused during surgery on the prostate, testes, or scrotum. You should be informed about the risks of surgery to your fertility by your surgeon before the procedure.

Sex and Ejaculation Issues

Problems with having sex or being able to ejaculate can affect your ability to conceive. This includes low libido (reduced or absent desire to have sex), erectile dysfunction (problems gaining or maintaining an erection), abnormal anatomy, or retrograde ejaculation (semen ejaculating backwards and therefore sperm moves towards the bladder instead of being released through the penis).

These issues may be physical or psychological in origin or a combination of both. Treatment may include medication, psychological therapy, or surgery.

The Men’s health forum provides lots of answers to infertility and sexual health and many other questions related to men’s health.

Unexplained Infertility

Approximately 1 in 4 (25%) of cases of infertility cannot be traced to any cause in either partner. This situation is classified as unexplained infertility and will be discussed in a future article.

Treatments for Infertility

If a cause is found, you should discuss treatment options with your doctor e.g., a urologist, fertility specialist, endocrinologist, GP (depending on the condition).

Treatment may involve medication, surgery, and/or Assisted Reproductive Technology (ART). Intracytoplasmic sperm injection (ICSI), Surgical Sperm Extraction, and Sperm freezing. ART will be discussed in a future article.

More information about male infertility can be found on the website of The British Association of Urological Surgeons.


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Is it taking longer than you hoped to get pregnant? Have you been assessed by your GP?

Written by GP, Dr Belinda Coker, our free guide will help you prepare for the fertility assessment consultation with your GP.

A guide to the fertility consultation with your GP by Dr Belinda Coker MRCGP




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