Given my small testicular volume but a normal semen analysis (56 million sperm per millilitre) and a normal total testosterone level (40 nmol per litre), am I infertile and do I require any treatment?

You Are Not Infertile and Do Not Require Treatment

With a sperm concentration of 56 million/mL—more than 3.5 times the WHO lower reference limit of 16 million/mL—and a normal testosterone level of 40 nmol/L, you have normal fertility parameters that do not require medical intervention. 1, 2

Understanding Your Sperm Count in Context

Your sperm concentration of 56 million/mL places you well above the fertility threshold:

• The WHO lower reference limit for normal sperm concentration is 16 million/mL (95% CI: 15-18 million/mL), meaning your count exceeds this by 350%. 1, 2
• Concentrations above 40 million/mL are associated with optimal fertility potential, and your count of 56 million/mL falls into this favorable range. 2
• Population studies demonstrate that fecundity increases progressively with sperm concentrations up to 40 million/mL, after which additional increases provide no further fertility advantage. 3, 4

Your testosterone level of 40 nmol/L (approximately 1,154 ng/dL) is robustly normal, well above the typical lower limit of 10-12 nmol/L (300-350 ng/dL), indicating healthy Leydig cell function and adequate hormonal support for spermatogenesis. 2, 5

Why Small Testicular Volume Does Not Predict Infertility in Your Case

The concern about small testicular volume must be interpreted in the context of actual sperm production, not volume measurements alone:

• Testicular volumes below 12 mL are associated with impaired spermatogenesis only when accompanied by elevated FSH (>7.6 IU/L), reduced sperm counts (<5 million/mL), or azoospermia. 2, 5, 6
• Your documented sperm concentration of 56 million/mL directly contradicts any functional testicular atrophy—you are producing sperm at a rate consistent with normal or above-normal testicular function. 2, 7
• Studies show that testicular volume correlates with sperm density, but this relationship breaks down when actual semen analysis is normal; 12% of infertile men have normal sperm parameters despite small testes, while 41% of fertile men have normal parameters. 8, 7

Critical distinction: True testicular atrophy causing infertility presents with sperm concentrations below 5 million/mL, elevated FSH, and often azoospermia—none of which apply to you. 2, 5

What Your Hormone Profile Tells Us

Without knowing your FSH and LH levels, we cannot fully characterize your hypothalamic-pituitary-testicular axis, but your normal testosterone and excellent sperm production argue strongly against primary testicular failure:

• Primary testicular failure (the condition associated with small testes and infertility) presents with low testosterone, elevated FSH (>7.6 IU/L), and severely reduced sperm counts (<5 million/mL)—you have none of these features. 2, 5
• Your normal testosterone indicates that intratesticular testosterone concentrations (which are 50-100 times higher than serum levels and essential for spermatogenesis) are adequate. 2
• If FSH were significantly elevated (>10-12 IU/L), it would suggest compensated testicular dysfunction, but your robust sperm production makes this unlikely. 2, 5

Do You Need Further Testing?

No urgent testing is required, but the following would provide reassurance and establish a baseline:

• Repeat semen analysis in 3-6 months to confirm stability of parameters, as single analyses can show natural variability. 1, 2
• Measure FSH, LH, and calculate free testosterone (using SHBG) to fully characterize your hormonal status and rule out compensated testicular dysfunction. 2, 5
• Physical examination by a urologist to assess for varicocele (which can cause progressive testicular damage even with currently normal counts), testicular consistency, and vas deferens patency. 1, 2

Genetic testing (karyotype, Y-chromosome microdeletions) is NOT indicated because these tests are reserved for men with severe oligospermia (<5 million/mL) or azoospermia—your count of 56 million/mL is 11 times higher than this threshold. 1, 2

Critical Actions to Protect Your Fertility

Even with normal current parameters, certain exposures can rapidly destroy spermatogenesis:

• Never use exogenous testosterone or anabolic steroids, as these completely suppress FSH and LH through negative feedback, causing azoospermia that can take months to years to recover—even after discontinuation. 1, 2, 5
• Avoid gonadotoxic medications (chemotherapy, high-dose corticosteroids) without first banking sperm if fertility is desired. 2, 5
• Optimize modifiable factors: smoking cessation, maintain healthy body weight (BMI <25), minimize scrotal heat exposure (avoid hot tubs, prolonged sitting, laptop use on lap). 1, 2
• Treat varicocele if present on examination, as correction of palpable varicoceles improves both semen quality and fertility rates, and can prevent progressive testicular atrophy. 1, 2

When to Seek Fertility Assistance

If you are actively trying to conceive:

• Couples with male TMSC (total motile sperm count) >10 million have excellent natural conception rates; your TMSC is likely 25-30 million (56 million/mL × volume × motility %), well above this threshold. 2
• Female partner age is the most critical factor: if she is under 30 years, expectant management for 12 months is appropriate; if she is 35-40 years, consider fertility evaluation after 6 months of timed intercourse. 2
• If no conception occurs after 12 months (or 6 months if female partner >35 years), proceed to fertility evaluation focusing on female factors first, as your sperm parameters are not limiting. 2

Common Pitfalls to Avoid

• Do not assume small testicular volume equals infertility—actual sperm production (documented by semen analysis) is the definitive measure of fertility potential. 2, 6, 8
• Do not start testosterone replacement "to improve fertility"—this is the single most common iatrogenic cause of male infertility and will cause azoospermia. 1, 2, 5
• Do not delay fertility evaluation of the female partner based on concerns about your testicular volume—your sperm parameters are normal and unlikely to be the limiting factor. 2

Bottom Line

You have normal fertility based on objective semen analysis and testosterone levels. Small testicular volume in the presence of normal sperm production likely represents constitutional variation (some men simply have smaller testes that function normally) rather than pathological atrophy. 2, 6, 8 No treatment is indicated, but establishing a hormonal baseline (FSH, LH) and monitoring semen parameters every 6-12 months would provide reassurance and detect any future decline early. 2, 5