Causes of Male Infertility

If you are worried about male fertility make an online video appointment with one of our NHS-trained GPs today.

IVF method used during treatment of the infertility

Written by Medical Professional

Treat it Online with Medicspot

Appointments Available Today

Infertility is a growing problem in the UK and across the world with rates increasing dramatically over the past 40 years. Around 40 to 50% of infertility is due to male infertility and around 2% of men are producing low quality or not enough sperm. Some of the reasons for the global decline in male fertility remain unclear, but there are some known causes and a few things you can do to reduce your risk. 

What causes male infertility?

Male fertility is dependent on 2 main factors:

  • Sufficient quantities of healthy sperm being produced in the testes 
  • Transportation of sperm from the testes during intercourse through erection and ejaculation

Problems in either of these areas will cause male infertility.

Problems with sperm production or poor quality of sperm

A low sperm count or oligozoospermia occurs when your body doesn’t make as much sperm as it should. Sometimes the cause of a low sperm count is unknown, but some causes of low sperm count include: 

  • Genetic disorders like Klinefelter syndrome where boys are born with an extra X chromosome
  • Hormonal imbalances like hypogonadism which causes low testosterone in males. Hypogonadism can be present at birth or develop later in life
  • Infections such as prostatitis (infection of the prostate gland) or sexually transmitted infections (STIs) like chlamydia and gonorrhoea
  • Being overweight or obese.
  • Some medications such as chemotherapy, some antibiotics and antidepressants, testosterone replacement therapy (TRT), and long-term use of anabolic steroids
  • Testicles becoming overheated
  • Smoking
  • Drinking too much alcohol
  • Use of recreational drugs like marijuana and cocaine
  • Being born with undescended testes

Problems affecting the transportation of sperm

Sometimes men who produce healthy sperm have fertility issues caused by blockages of the tubes in the testes, or problems with erection or ejaculation that prevents the transportation of sperm. This may include: 

  • Surgery or injury to the testicles 
  • Structural problems such as blockages in the tubes that carry sperm
  • Swollen veins in the testicles (varicocele)
  • Erectile dysfunction (difficulty getting or keeping an erection long enough to have sex)
  • Retrograde ejaculation that occurs when semen is ejaculated backwards into the bladder instead of out of the body through the penis 

Anejaculation is when there is no semen released during sexual climax. This may be due to birth abnormalities, surgery, spinal cord injury or medical conditions like diabetes and multiple sclerosis

Can HPV cause infertility in males?

Human papillomavirus (HPV) is a common sexually transmitted infection that can affect both males and females. Infection with HPV can lead to genital warts in both sexes and cervical cancer in women. 

Until recently, HPV infection in men was not thought to pose a significant risk to health, as it is unlikely to lead to problems like cancer. But a 2013 study concluded that men infected with HPV produced lower quality sperm and had an increased risk of male infertility

A further review found that HPV infection in males could be responsible for the decrease in the fertility rate, though more research is needed. 

In the UK, men are not routinely screened for HPV, but if you feel you may have been exposed to the virus, or experience any symptoms like genital sores, lumps, rashes, pain, discharge from your penis, or genital warts make an appointment with your local sexual health clinic or GP.

Can IBD and Crohn's disease cause infertility in males?

Inflammatory bowel disease (IBD) refers to 2 chronic (long-term) conditions that cause inflammation of the gut; ulcerative colitis and Crohn’s disease. 

Studies have suggested a link between IBD and infertility, but it is unclear whether it is the disease itself that causes the problem or some of the treatments for the condition. 


Some possible causes of reduced fertility among men with IBD include: 


  • Some medications like sulfasalazine can temporarily reduce male fertility.
  • Surgery. Rarely, surgery for IBD like colostomy and ileostomy surgery can result in infertility.
  • Erectile dysfunction is more common in men with moderate to severe IBD.
  • Psychological factors. Some people with IBD fear passing the condition onto their children, so may decide not to have a family. Depression is also common in people with chronic diseases which may impact sex drive and desire for children. 
  • Poor nutrition. IBD can make it difficult to absorb vital nutrients such as zinc, which may lead to reduced fertility. 

If you have IBD and are worried about infertility, make an appointment to see a GP. 

Can haemorrhoids cause male infertility?

Haemorrhoids or “piles” are swollen veins in the anus or rectum (back passage) that can bleed and may cause discomfort, itching, and pain.

Though haemorrhoids don’t directly cause male infertility, they are linked to erectile dysfunction (difficulty getting or keeping an erection), especially in younger men. If you have bleeding from your anus, you must be checked by a doctor to determine the cause, so make an appointment with a GP. 

Can herpes cause infertility in males?

Herpes is a sexually transmitted infection (STI), that can affect both males and females. Symptoms include an itching, tingling, or burning sensation around your genitals, blisters and sores on your genitals, thighs, or anus, and pain when peeing. 

Studies have shown a significant link between herpes infection and reduced sperm count in males. Herpes isn’t curable, but flare-ups can be treated with medication to reduce symptoms. 

If you have symptoms of herpes or think you may have been exposed to the herpes virus, make an appointment with your local sexual health clinic or GP.  

Do smoking and drinking affect male fertility?

While it is well known that smoking and excessive alcohol consumption can severely damage your health, the link between smoking and heavy drinking and male fertility is not as clear. 

One study found that smoking and alcohol intake did not affect either the quality or quantity of sperm, while another concluded that heavy smoking was linked to decreased sperm counts and excessive alcohol consumption caused an increase in misshapen sperm. 

Smoking not only damages your health, but it can also cause health problems in your baby such as asthma, an increased risk of respiratory (breathing) problems, and cot death. If you are trying to start a family, it’s best to kick the habit before the baby arrives. Drinking too much alcohol increases the risk of liver and heart problems as well as some cancers, so stick to safe limits. 

Can chemotherapy cause infertility in males?

Chemotherapy is a medical treatment for cancer that works by killing cancer cells in the body. Some chemotherapy medications can damage sperm in men and sperm-forming cells in boys which can lead to infertility. Chemotherapy can cause temporary or permanent infertility by: 

  • Making you produce less sperm 
  • Affecting production of the male hormone testosterone
  • Making your sperm less effective at fertilising an egg
  • Affecting the nerves to your penis making it more difficult to get an erection (this is usually temporary)

If you have been diagnosed with cancer and would like to start a family, talk to your doctor about storing your sperm in a sperm bank before starting treatment. This will preserve your healthy sperm for when your treatment is finished. 

Can chlamydia make men infertile?

Chlamydia is the most common sexually transmitted infection in the UK. While it is commonly known that untreated chlamydia can lead to infertility in females, the infection can also damage sperm and cause infertility in males. 

Early treatment with antibiotics can prevent infertility in both men and women, so get tested for chlamydia and start any necessary treatment as soon as possible. Because chlamydia is so common and often doesn’t have any symptoms, the NHS recommends having a chlamydia test once a year if you are under 25 and having unprotected sex with new or multiple partners. 


Male infertility is a complex issue with many causes, some of which are only just beginning to be understood. As with most health conditions, early diagnosis and treatment are essential for the best outcomes. 

If you are worried about male infertility make an appointment with your GP. 

Alternatively, you can book an online video consultation with Medicspot to discuss your concerns with one of our NHS-trained GPs. 

At Medicspot we also provide at-home test kits for you to test your fertility yourself in the privacy of your own home. 


Oxford Academic. Human Reproduction Update. Temporal trends in sperm count: a systematic review and meta-regression analysis November-December 2017 (Accessed August 15th, 2022) 

NHS: Low sperm count August 7th, 2019 (Accessed August 15th, 2022)

PubMed: Nonsurgical Management of Oligozoospermia June 25th, 2020 (Accessed August 15th, 2022)

PubMed: Correlation between HPV sperm infection and male infertility April 22nd, 2013 (Accessed August 15th, 2022)

Hindawi. Biomed Research International: Male and Couple Fertility Impairment due to HPV-DNA Sperm Infection: Update on Molecular Mechanism and Clinical Impact—Systematic Review March 25th, 2014 (Accessed August 15th, 2022)

PubMed: Infertility in men with inflammatory bowel disease August 6th, 2016 (Accessed August 15th, 2022)

Gastroenterology and Hepatology: Sexual Issues and Fertility in Male Patients With Inflammatory Bowel Disease September 2020 (Accessed August 15th, 2022)

PubMed: Haemorrhoids are associated with erectile dysfunction: a population-based study December 2012 (Accessed August 15th, 2022)

The Journal of Biomedical Research: Asymptomatic seminal infection of herpes simplex virus: impact on male infertility January 2013 (Accessed August 15th, 2022)

PubMed: Effect of alcohol intake and cigarette smoking on sperm parameters and pregnancy December 11th, 2012 (Accessed August 15th, 2022)

PubMed: The effects of smoking and alcohol intake on sperm quality: light and transmission electron microscopy findings 2012 (Accessed August 15th, 2022)

NIH National Cancer Institute: Fertility Issues in Boys and Men with Cancer February 24th, 2020 (Accessed August 15th, 2022)

PubMed: Impact of cancer and cancer treatment on male fertility October-December 2015 (Accessed August 15th, 2022)

Cancer Research UK: Men’s fertility and chemotherapy September 8th, 2020  (Accessed August 15th, 2022)

New Scientist: Chlamydia reduces male fertility by ravaging sperm October 15th, 2007 (Accessed August 15th, 2022)

Mayo Clinic: Retrograde ejaculation (Accessed August 15th, 2022)