What a semen analysis really means
A semen analysis is the main first-line test used to assess male fertility. It measures the semen itself and several features of sperm, but it does not give a simple “fertile” or “infertile” answer. Results need to be interpreted as a pattern, together with your medical history and your partner’s fertility circumstances.[1–4]
If you already have a report, you can also use the Semen Analysis Interpreter for a plain-English explanation of the individual measurements.
What do the numbers mean?
The World Health Organization (WHO) publishes reference values based on men whose partners conceived naturally within 12 months. Current lower reference limits include:[1,5]
Semen volume: 1.4 mL
Sperm concentration: 16 million/mL
Total sperm number: 39 million per ejaculate
Progressive motility: 30%
Total motility: 42%
Normal morphology: 4%
These are not pass/fail cut-offs. A result below one of these values does not prove infertility, and a result above them does not guarantee pregnancy. Fertility depends on several sperm measures acting together, as well as both partners’ reproductive circumstances.[1,2]
Count, motility and morphology: which matters most?
There is no single “most important” number.
Sperm concentration tells us how many sperm are present in each millilitre. A persistently reduced concentration is called oligozoospermia and may justify assessment for causes such as hormonal problems, varicocele, testicular conditions, medications, genetic factors or testosterone/anabolic steroid exposure.[2–4] Read more about low sperm count.
Motility describes how well sperm move. Progressive motility is particularly relevant because sperm need forward movement to reach an egg. A low result may occur alone or together with a reduced sperm count.
Morphology describes the percentage of sperm meeting strict laboratory criteria for normal shape. Because the WHO lower reference value is only 4%, a morphology result that looks “very low” on paper may be less concerning than patients expect. It should not be interpreted in isolation.[1,2]
What if no sperm are seen?
No sperm detected in the ejaculate is called azoospermia. This requires confirmation and further assessment because it may result from either a blockage or significantly reduced sperm production. These can have very different fertility pathways.[2–4]
Read more about azoospermia.
Why might the test need repeating?
Semen results naturally vary between samples. Recent fever or illness, the abstinence period, incomplete collection and laboratory or transport factors can affect the result.
Australian and European guidance recommends repeating an abnormal semen analysis before making major conclusions. The Australian guideline recommends a second analysis at approximately six weeks, or later when clinically appropriate.[2,4]
Does an abnormal result tell you the cause?
Usually not. A semen analysis can identify a pattern, but it does not by itself explain why that pattern exists. Further assessment may include a reproductive and medical history, examination, hormone testing and, in selected cases, genetic testing or imaging.[2–4]
Relevant causes may include varicocele, previous testicular problems, obstruction, or suppression of sperm production from testosterone or anabolic steroids.
When should you seek specialist review?
Consider specialist male fertility assessment if sperm are absent, the count is very low, abnormalities persist on repeat testing, there are known fertility risk factors, or pregnancy has not occurred despite appropriate attempts. Both partners should usually be assessed in parallel.[2–4]
For patients in Brisbane, elsewhere in Australia or overseas, existing semen analyses and fertility records can often be reviewed before deciding what further testing is required.
Explore Male Infertility & Reproductive Urology, see International Patient Information, or request an appointment.
Medical disclaimer
This information is for general education only and does not replace individual medical advice. A semen analysis cannot diagnose fertility or infertility on its own. Results should be interpreted by an appropriately qualified clinician in the context of both partners’ reproductive circumstances.
References
World Health Organization. WHO laboratory manual for the examination and processing of human semen. 6th ed. Geneva: World Health Organization; 2021.
European Association of Urology. EAU Guidelines on Sexual and Reproductive Health. EAU Guidelines Office; 2026.
American Urological Association; American Society for Reproductive Medicine. Diagnosis and Treatment of Infertility in Men: AUA/ASRM Guideline. 2020; amended 2024.
Katz DJ, O'Donnell L, McLachlan RI, Moss TJ, Boothroyd CV, Jayadev V, et al. The first Australian evidence-based guidelines on male infertility. Med J Aust. 2025;223(11):653-663. doi:10.5694/mja2.70080.
Campbell MJ, Lotti F, Baldi E, et al. Distribution of semen examination results 2020: a follow up of data collated for the WHO semen analysis manual 2010. Andrology. 2021;9(3):817-822. doi:10.1111/andr.12983.
