The investigation of the male partner is fairly simple and involves an examination of a specimen of semen. This is to assess the number of sperms, the percentage of abnormal sperms and the activity of live sperms. A reasonable count would have a sperm concentration of at least 20 million per ml of semen. Around half of these sperm should be active and no more than 40% appear abnormal. Other tests may be performed, including an assessment of twenty-four hour survival. Further specialised investigation of the male partner could follow depending on the results of the initial sperm assessment.

In order to perform a semen analysis, the male partner will be required to produce a semen sample, by masturbation, 48-72 hours after the most recent ejaculation. The ejaculation will have to be into a clean container, which will be provided by the clinic. For most couples, this may be performed at home and the sample be brought to the clinic as soon as it is produced. For other couples, perhaps living further away, the clinic has facilities where the sample can be produced.