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medically accurate illustration of human sperms

Causes of Male Infertility

Around 30% of fertility challenges are related to female factors, around 30% to male, 20% to both male and female and 20% is unexplained.

But the good news is that in most cases, male infertility is treatable with the right diagnosis, support and treatment.

Main causes of Male Infertility

Sperm Quality & Quantity

The most common cause of infertility in men involves abnormal or insufficient sperm. Problems can arise when either not enough sperm is being produced, or the sperm is of poor quality.

The motility can be low, which affects the sperm's ability to ‘swim’ as vigorously as it needs to, or the sperm can be abnormally shaped. A normal sample will show ~20 million sperm per millilitre, at least half of which will be active. Intra-Cytoplasmic Sperm Injection (ICSI) can help to overcome certain male fertility problems caused by low sperm count or poor sperm quality. There is also a range of male diagnostic tests we can perform to identify if there are any issues with the sperm.

Blocked tubes

Either the tubes which store and carry your sperm from your testicles or the vas deferens which lead from them and carry sperm immediately prior to ejaculation can be blocked.

If everything else is healthy then a simple procedure to retrieve sperm may be the recommended way forward.


The testicles produce and store your sperm. If they are damaged it will affect the quality and quantity of the sperm you produce.

The damage could be caused by a wide number of events such as an infection or a testicular operation. If this is the case, it may still be possible to retrieve sperm surgically.


Sulfasalazine used to treat rheumatoid arthritis and Crohn's disease can decrease your sperm count, however the effects are only temporary and you should return to normal after your course of treatment. Long term use and abuse of anabolic steroids will reduce the number of sperm you produce and affect their motility.

The drugs involved with chemotherapy can severely reduce your production of sperm, however, advances in sperm freezing now mean that if you have to undertake a course of chemotherapy you can take the precaution of freezing sperm in advance of your treatment.