WHO 6th edition (2021) lower reference limits: semen volume 1.4 mL, concentration 16 million/mL, total sperm number 39 million, progressive motility 30%, normal forms 4%. WHO states these do not represent a limit between fertile and infertile men.
Male fertility: sperm health, tests and treatment
Get tested early
Male factor is involved in a substantial proportion of cases and is typically symptomless. Semen volume and appearance tell you nothing about count, motility or shape — men with azoospermia have entirely normal-looking ejaculate.
A semen analysis is quick, inexpensive and non-invasive. It should be among the first tests, not arranged after the female partner has been fully investigated.
Reading the report
WHO 6th edition (2021) lower fifth percentile values:
| Parameter | Value |
|---|---|
| Semen volume | 1.4 mL |
| Concentration | 16 million/mL |
| Total sperm number | 39 million per ejaculate |
| Total motility | 42% |
| Progressive motility | 30% |
| Normal forms | 4% |
What these are not: WHO states plainly that the lower fifth percentile "does not represent a limit between fertile and infertile men", and notes substantial overlap between fertile and infertile men. These describe where 95% of men who conceived naturally within a year fell.
Check which edition your laboratory used — the 5th edition (2010) figures differ and are still widely quoted.
Total sperm number matters more than concentration — WHO notes it has greater diagnostic value.
One number tells you little
Results carry most weight when multiple parameters are abnormal. Except for azoospermia and a few defined conditions, no single parameter is highly predictive.
Always repeat an abnormal result. Parameters vary substantially between samples.
Treatment
Varicocele repair — consider where palpable and semen parameters abnormal and the couple infertile. Not recommended for non-palpable varicoceles found only on imaging.
Azoospermia — extended search of the centrifuged sample finds rare sperm in up to 35% of men previously called azoospermic. Genetic testing before any surgery: complete AZFa or AZFb deletion means sperm have not been retrieved by TESE, so surgery is not indicated.
Testosterone — must not be prescribed to a man interested in current or future fertility. It suppresses sperm production and can cause azoospermia. Gym supplements are a recognised hidden source of anabolic steroids.
Supplements — a Cochrane review of 90 trials found a possible live birth benefit that disappeared when high-risk-of-bias studies were removed. Very low certainty, described as inconclusive.
Three months
Sperm production takes roughly 72 to 90 days. Allow that long before repeating a test after any change. Most people expect faster results and stop too early.
Sources
- WHO laboratory manual, 6th edition (2021)
Frequently Asked Questions
What is a normal sperm count?▾
Per WHO 2021: ≥16 million sperm per mL (≥39 million total per ejaculate) is the lower reference limit. For fertility assessment, Total Motile Sperm Count (TMSC) is more useful: above 20 million is normal, 5–20 million is mildly reduced, below 5 million is severe male factor requiring IVF with ICSI.
What causes low sperm count?▾
The most common causes are: varicocele (35% of infertile men — most common correctable cause), idiopathic (~30%, no identified cause), genetic disorders (Klinefelter syndrome, Y-chromosome microdeletions), hypogonadotropic hypogonadism (very treatable with FSH/hCG injections), and lifestyle factors (smoking reduces count 15–20%; anabolic steroids completely suppress production; heat exposure from laptops or hot baths).
Can low sperm count be treated?▾
Yes — many causes are treatable. Varicocele repair improves parameters in 60–70% of men (ASRM Grade A). Hormonal treatment (FSH + hCG) for hypogonadotropic hypogonadism restores sperm in 70–80% within 6–18 months. A 3-month antioxidant and lifestyle protocol improves lifestyle-related oligospermia. Even for azoospermia, PESA gives >90% retrieval for obstructive cases; micro-TESE gives 40–60% for non-obstructive.
When do you need IVF for male infertility?▾
IVF with ICSI is recommended (ASRM 2023) when TMSC falls below 5 million after preparation, sperm are surgically retrieved, previous IVF produced no fertilisation, or sperm DNA fragmentation is very high (>25%). For mild-to-moderate male factor (TMSC 5–20 million), 3–6 IUI cycles are a reasonable first step before IVF.