Man holding baby

Male infertility is assessed initially on a semen analysis. This is not a particularly accurate method of assessing male infertility unless there are no sperm at all. If this is the case (Azoospermia) then clearly conception will not happen naturally.

The sperm test (see instructions) measures volume of ejaculate, count, proportion of moving sperm (motility) , the number of normally shaped sperm and in some laboratories anti sperm antibodies.

There are normal values for all these parameters. Currently these are:

  • Volume 2-5ml
  • Count over 15 million per ml of ejaculate
  • Motility 40% progressively moving sperm
  • Abnormal forms less than 4% normally shaped sperm

These are calculated from a fertile population and represent the bottom 5%. They do not clearly show that fertility is OK above that level and poor below.

Because the number of normally shaped sperm are low even in the normal situation it is important that your test is done in an experienced laboratory. The best ones are those that also do IVF/ICSI.

Critical Sperm Values

  • Volume under 1 ml (check that the whole sample has been collected)
  • Count under 5 million per ml of ejaculate
  • Motility 20% progressively moving sperm
  • Abnormal forms 100%

In these situations fertility is normally severely impaired.

A low ejaculate volume may be the result of difficulty in collecting the whole sample or if repeated a problem with sperm production.

A low count may represent a hormonal problem or may represent the best sample that the testes are capable of. If very low it might suggest a genetic abnormality or testicular failure.

Low motility may be the result of infection, low antioxidants in the diet, exposure to toxins or immature sperm.

High numbers of abnormal sperm may represent exposure to toxins or poor sperm construction. The abnormal forms represent an abnormality of sperm shape. They do not suggest that the sperm are genetically abnormal and although it might reduce fertility it will not increase the risk of an abnormal baby.

All humans produce quite a high number of abnormally shaped sperm compared to other mammals.

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Sperm Production

The testis continually makes sperm. It takes approximately 72 days to make a sperm from initial stages to a fully mature sperm. Ejaculated sperm started their journey 72 days before.

This means that if you have an abnormal sperm test you should repeat the test at least 72 days later before coming to a conclusion. We advise 3 months between tests. If your second test 3 months later is the same as the first test then it is likely to be a constant feature and you will be advised as to the best treatment.

If you have any treatment for a sperm abnormality then wait 3 months for a repeat test to see if treatment has helped. If there is no change at 3 months then it is unlikely that this treatment will help. You should either change treatment or consider assisted conception (IVF/ICSI)

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Some men have unexplained sperm problems often called idiopathic. Generally empirical treatments (without foundation) are pretty unsuccessful at raising count, improving motility or reducing abnormal forms so our recommendation is that if there is no plausible reason for the abnormality then treatment is unlikely to be successful. Vitamin supplementation is not harmful and could be used in any case. Omega 3 and Selenium may be useful here as they have been shown to increase sperm count in some men. Note that increasing count is poorly associated with increasing fertility.

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This may affect men with severely reduced count or no sperm. They may have a genetic defect which is permanent.


There is an inverse relation between fertility and weight. If you are overweight then every extra 10Kg may reduce fertility by 15%.

The count is lower and some men have some erectile dysfunction. Many environmental toxins are fat soluble. Increased weight also increases insulin resistance which is why the older obese man is more prone to diabetes in later life.

Men with central adiposity are more affected. If you have a high level of saturated fat in your diet there is some evidence that it worsens the sperm motility and abnormal forms.

Taking omega 3 may help

It does not seem to affect the chance of successful IVF or ICSI however

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DNA fragmentation

There is growing evidence that the DNA in the sperm (the genetic material in the sperm head) of subfertile men is more susceptible to damage. This is thought to affect the chance of natural conception. Neither the tests used to test for DNA fragmentation nor the results are yet able to fully identify individual men with a problem.

What is clear is that there may be an issue with normal fertilisation both in vivo and in vitro but it is not clear if this affects pregnancy rates in vitro. Intrauterine insemination pregnancy rates are reduced. There is dispute as to whether this issue is associated with miscarriage or not.

There is one study that suggests that sperm ejaculated in a second ejaculate soon after the first ejaculate may have significantly less DNA damage than in the first ejaculate.

Antioxidants may help in this situation.

Routine testing remains controversial.

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Important toxins


Smoking reduces sperm motility and increases the number of abnormally formed sperm. This is partially because of hydrocarbons (the same chemicals that increase the risk of lung cancer) and partially because of the exposure to cadmium. This is a toxic heavy metal found in cigarette smoke. This is reversible. If you stop smoking then it will take about 3 months to have any effect.

Smoking both affects male and female fertility, even passive smoking.

Heavy metal exposure

Heavy metal exposure can harm sperm The commonest are Lead, Mercury, and Cadmium. The risk is greater is industries such as printing (dyes contain heavy metals), metal processes and battery manufacture. If you are given protective gear then use it.


Toxic solvents can affect sperm production, especially aromatic solvents.

Anabolic steroids

These seriously affect sperm production. The effect is often permanent. Dosage is often arbitrary and given by an unqualified gym coach. Drugs are usually pharmaceutical grade. Not only does it do permanent damage to your sperm production but it also damages you lipids (blood fats) and increases the risk of heart attack in the long term. It does not affect the sperms genetic qualities so there is no increased risk of an abnormal baby , so treatments such as ICSI are still possible

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Anti-sperm antibodies

These are no longer routinely tested for. There is no evidence that steroid treatment helps (by reducing immune response). Usually if significant, the other parameters measured in the sperm count are abnormal too. It has no effect on fertilisation by ICSI

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