About 25% of all infertility is caused by a sperm defect and 40-50% of infertility cases have a sperm defect as the main cause, or a contributing cause.

• It is sometimes hard to know whether the sperm problem is the only cause, or just a contributing cause to the infertility. Part of the problem is that numbers are just numbers:

• Men with very low sperm counts can sometimes have children

• Some men with normal sperm counts can be infertile

What matters is not really how many or how fast they swim - but whether they can fertilize the female partner's eggs. This is really a biochemical issue at the molecular level - looking at the little swimmers under the microscope is not a perfect way of assessing the ability of the sperm to fertilize the wife's eggs.

This is a very simple and important test and should be done early in the evaluation process. Sometimes the test should be done 2, or even 3 times to get an accurate reflection of the numbers and their variation over time.

Cutoff values for "normal" vary somewhat, depending on the lab and the interpreter, but the World Health Organization defines these as normal values:

If a severe sperm defect is discovered, the testing on the female partner might be more limited. Treatment, such as inseminations or in vitro fertilization can then be started more directly.

Further testing on the male with an abnormal semen analysis

In some cases we do hormone (blood) tests on men with abnormal semen analysis. This can (rarely) sometimes identify a reason for the abnormality. Occasionally, the problem will be treatable in the male.

Sperm function tests

Sperm penetration assay, also called the hamster egg test: In this test, the husband's sperm is mixed with hamster eggs to see whether they penetrate the eggs. It is expensive and there are many false positives and also false negative results. Some men are better with the hamster than with the wife... etc. We do not do this test.

Human zona binding assay: In this test, the husband's sperm is mixed with pieces of human egg shells (zona pellucidas) to see how many will bind to the shells. There are a lot less false positives and false negative results as compared to the hamster egg test. However, human egg shells are not readily available for this use - so it is not a very practical test.

Sperm antibody testing

• Sperm antibodies in the blood of men or women do not affect fertility
  

• Antibodies on the head of the sperm can cause failure of fusion with the egg

• Spontaneous pregnancy rates are higher in couples without these antibodies, however, fluctuations are seen even without any therapy. Also, since inseminations are used as treatment for both unexplained infertility and for sperm antibodies, many infertility specialists feel that the costs of this test are not justified.

Varicocele

In some cases the man is referred to a urologist to assess whether he might have a correctable condition called a varicocele. However, correcting a varicocele (surgical procedure) many times will not improve the semen quality enough to change the mode of therapy that will be required to result in a pregnancy for the couple. In other words, if a couple will need IVF anyway, why bother with surgery for a varicocele. These treatment options depend on the degree of abnormality in the semen and other factors involved in the individual couple's case.