In an adult male with a testicular volume of 9 ml but normal sperm concentration, total testosterone, follicle‑stimulating hormone (FSH) and luteinising hormone (LH) levels, what is the clinical significance of the reduced testicular size?

Understanding Your Testicular Volume and Fertility Parameters

Your 9 ml testicular volume is definitively small and indicates reduced testicular reserve, but your normal sperm production (60 million/ml) and testosterone (40 nmol/L) demonstrate that your testes are still functioning adequately despite their size—this apparent paradox occurs because testicular function depends on the quality of remaining seminiferous tubules, not just total volume. 1, 2

Why Small Testes Can Still Produce Normal Sperm

Testicular volume below 12 ml is classified as atrophic and typically correlates with impaired spermatogenesis, but this relationship is not absolute. 2 Your case illustrates an important clinical principle: some men maintain focal areas of active spermatogenesis even with reduced testicular size. 1

• Your sperm concentration of 60 million/ml far exceeds the WHO lower reference limit of 16 million/ml, placing you well within the normal fertile range despite your small testicular volume. 3
• Your testosterone level of 40 nmol/L (approximately 1150 ng/dL) is in the high-normal to elevated range, which argues strongly against primary testicular failure. 1
• Your FSH of 9.5 IU/L and LH of 7 IU/L are both in the upper-normal range, indicating your pituitary is working harder to maintain normal function—this is compensated testicular dysfunction, not complete failure. 1

What Your Hormone Pattern Reveals

The combination of borderline-elevated FSH with normal LH and high-normal testosterone indicates reduced testicular reserve with successful compensation. 1 This pattern means:

• Your pituitary gland is producing more FSH to stimulate the smaller amount of testicular tissue you have, which is why FSH sits at 9.5 IU/L (upper end of your reference range). 1
• FSH levels >7.6 IU/L typically indicate some degree of testicular dysfunction, but your actual sperm production proves this dysfunction is mild and well-compensated. 1
• Your normal LH (7 IU/L) and elevated testosterone demonstrate that Leydig cell function (testosterone production) is preserved, which is essential for maintaining the high intratesticular testosterone needed for spermatogenesis. 1

Critical Factors That Explain Your Situation

Testicular volume correlates with sperm production on a population level, but individual variation is substantial. 4, 5, 6 Research shows:

• Men with testicular volumes of 10-12 ml typically have oligospermia rather than azoospermia, with FSH levels >7.6 IU/L indicating impaired but not absent spermatogenesis. 1
• Biofunctional sperm parameters (mitochondrial function, DNA integrity) worsen with decreasing testicular volume, but your normal sperm count suggests your remaining testicular tissue is high-quality. 4
• Critical total testicular volume for normal function is approximately 20 ml by ultrasound or 30-35 ml by Prader orchidometer, meaning your bilateral volume of ~18 ml (9 ml × 2) falls below this threshold but still permits adequate sperm production. 5

Why This Matters for Your Future

Your reduced testicular reserve means you have less capacity to compensate if additional stressors occur. 1 Key risks include:

• Exogenous testosterone or anabolic steroids will completely suppress your spermatogenesis through negative feedback, potentially causing azoospermia that takes months to years to recover—never use these if you want to preserve fertility. 1
• Varicocele, if present, could accelerate testicular damage—you should be examined for a palpable varicocele, as repair can stabilize or improve testicular function in men with your profile. 7, 8
• Progressive decline in sperm parameters is possible, so repeat semen analysis every 6-12 months is essential to detect early deterioration. 1

Essential Next Steps

You need a complete fertility evaluation to understand the cause of your small testicular volume and protect your future fertility. 1, 2

Mandatory Testing

• Repeat semen analysis in 2-3 months to confirm your parameters are stable, as single analyses can be misleading due to natural variability. 3
• Physical examination by a urologist or reproductive specialist to check for varicocele (present in up to 40% of infertile men), testicular consistency, and vas deferens abnormalities. 1, 7
• Scrotal ultrasound with Doppler to accurately measure testicular volume using the Lambert formula (Length × Width × Height × 0.71), assess for varicocele, and exclude structural pathology. 2

Genetic and Hormonal Workup

• Karyotype analysis is strongly recommended because men with small testes (<12 ml) and borderline-elevated FSH have increased risk of chromosomal abnormalities like Klinefelter syndrome (47,XXY). 1, 2
• Y-chromosome microdeletion testing should be performed if your sperm count ever drops below 5 million/ml, as complete AZFa or AZFb deletions predict near-zero sperm retrieval success. 1
• Measure SHBG and calculate free testosterone to ensure your bioavailable testosterone is adequate, as high SHBG can reduce the testosterone available to support spermatogenesis. 1
• Check thyroid function (TSH, free T4) because thyroid disorders commonly affect reproductive hormones and can elevate FSH. 1
• Measure prolactin to exclude hyperprolactinemia, which can disrupt gonadotropin secretion. 1

Fertility Preservation Strategy

Given your reduced testicular reserve, you should strongly consider sperm cryopreservation now while your parameters are normal. 1

• Bank 2-3 separate ejaculates (with 2-3 days abstinence between collections) to provide backup samples and maximize future fertility options. 1
• This provides insurance against progressive decline, because once azoospermia develops, even microsurgical testicular sperm extraction (micro-TESE) only achieves 40-50% sperm retrieval rates. 1
• Sperm cryopreservation can be performed via mail-in kits if access to andrology laboratories is limited. 1

Common Pitfalls to Avoid

• Do not assume your fertility is guaranteed long-term just because your current sperm count is normal—your reduced testicular reserve means you are at higher risk for future decline. 1, 8
• Avoid heat exposure to the testes (hot tubs, saunas, tight underwear, laptop use on lap), maintain healthy body weight (BMI <25), and stop smoking if applicable. 1
• Never start testosterone replacement therapy without first banking sperm, as it will cause complete suppression of spermatogenesis. 1

What Your Numbers Actually Mean

Your fertility potential right now is good, but your trajectory is uncertain. 3, 8

• Sperm concentration of 60 million/ml is nearly 4 times the WHO lower reference limit, indicating excellent current fertility. 3
• Testicular volume of 9 ml per testis (18 ml total) is below the critical threshold of 20 ml total, which correlates with increased risk of oligospermia in population studies. 5, 8
• Infertile men with varicoceles have mean testicular volumes of 17.6-18.7 ml, similar to your total volume, and significantly smaller than fertile controls (23-25 ml). 7

The bottom line: your testes are small but currently functional, and proactive monitoring plus fertility preservation will protect your reproductive future. 1, 2, 8