Male Infertility

After a woman’s age, clinical studies show, male infertility is the single biggest factor affecting a couple’s chance of conceiving. The quality of a man’s sperm declines with age, although not as significantly as the decline in egg quality experienced by women. The good news is that the most common causes of male infertility are easily diagnosed, and most can be treated.

Age and Infertility

Age is a factor that impacts on fertility for both men and women. By the age of 40, a woman’s chance of conception is greatly reduced. By the age of 44 years chance of success is around 1% per cycle. In men, the number and quality of sperm may decline with age, particularly if there are co-existing health or lifestyle problems.

Whilst the suitability of IVF for men and women over 45 years of age is ultimately a clinical one, you should consider this carefully when consulting your GP.

Lifestyle Factors that can affect fertility


Research suggests that obesity may negatively affect sperm quality, reducing both sperm count and movement.


Men who smoke cigarettes are more likely to have low sperm counts. Smoking can also decrease sperm movement and cause sperm to be malformed.  If you smoke, our doctors can help you quit today.


Heavy drinking can reduce the quality and quantity of sperm.


Drug use, including steroids, can decrease sperm movement and cause sperm to be malformed.

Medical conditions that can affect fertility

Sperm disorders

Problems with the production and maturation of sperm are the most common causes of male infertility.

Sperm may be immature, abnormally shaped (poor morphology), or unable to move properly (poor motility). Normal sperm may also be produced in abnormally low numbers (oligospermia) or seemingly not at all (azoospermia).

In rare cases (among men who have undergone vasectomy reversals), the immune system can develop antibodies to the sperm, potentially harming them as they are produced.

Dilated veins around the testicle

This condition, known as varicocele, increases the temperature in the scrotum, which can result in fewer sperm being produced as well as malformed or malfunctioning sperm.

Damaged sperm ducts

Blockage or scarring in the sperm ducts (or vas deferens) prevents the sperm from reaching the seminal fluid.

Hormone deficiency

Insufficient release of hormones that stimulate sperm production can reduce the number of sperm.


Difficulty obtaining or maintaining and erection can result in the male being unable to ejaculate inside the vagina.

Incidental causes

Damage caused by major abdominal disease, surgery, therapy (such as chemotherapy), tumours, drug exposure, or physical trauma can affect fertility.