Can men with elevated Follicle-Stimulating Hormone (FSH) levels and normal testosterone levels still father children naturally?

Yes, Men with FSH 10-12 Can Father Children Naturally

Men with FSH levels of 10-12 IU/L and normal testosterone can indeed father children naturally, as FSH shows natural biological variation among healthy fertile men, though these borderline-elevated levels warrant semen analysis to confirm normal sperm production rather than assuming fertility is unaffected. 1, 2

Understanding the Clinical Context

FSH levels in the 10-12 IU/L range represent a gray zone where biological variation overlaps with early testicular dysfunction:

• Some men maintain FSH levels of 10-12 IU/L throughout life while preserving completely normal fertility and testosterone production 1, 2
• However, FSH is negatively correlated with spermatogonia numbers—higher FSH reflects the pituitary's compensatory response to reduced testicular function 1, 3
• Research shows that FSH >4.5 IU/L is associated with increased risk of abnormal sperm concentration and morphology, with risk escalating as FSH rises 4

The Critical Distinction: FSH Alone Cannot Predict Fertility

The fundamental clinical principle is that FSH levels alone cannot definitively predict fertility status or actual sperm production. 3, 2

Key evidence supporting natural conception with FSH 10-12:

• Men with maturation arrest can have normal FSH despite severe spermatogenic dysfunction, while others with elevated FSH maintain adequate sperm production 1, 2
• Among childhood cancer survivors, 77% of men who achieved conception did so naturally, though all who required assisted reproductive technology had elevated FSH 5
• The predictive threshold for significant fertility impairment appears closer to FSH >12.1 IU/L (95th percentile) rather than 10-12 IU/L 3

Essential Diagnostic Steps

Rather than reassuring based on FSH alone, obtain objective fertility assessment:

• Perform comprehensive semen analysis (at least two samples, 2-3 months apart after 2-7 days abstinence) to directly assess sperm production 1, 3
• Measure complete hormonal panel including testosterone, LH, and prolactin to evaluate the entire hypothalamic-pituitary-gonadal axis 1, 3
• Conduct focused physical examination specifically evaluating testicular volume and consistency—normal-sized testes with FSH of 10-12 suggest better prognosis than atrophic testes 3

Addressing Reversible Factors

Before concluding FSH 10-12 represents permanent baseline:

• Borderline FSH levels (9-12 IU/L) often normalize to 7-9 IU/L after addressing metabolic stressors including obesity, acute illness, or other reversible factors 1
• Weight loss through low-calorie diets can reverse obesity-associated secondary hypogonadism by improving testosterone levels and normalizing gonadotropins 1
• Avoid hormonal testing during acute illness or metabolic stress, as transient conditions artificially elevate FSH and suppress the hypothalamic-pituitary-gonadal axis 1

Critical Management Pitfalls

Never prescribe testosterone therapy to men interested in current or future fertility—testosterone provides negative feedback to the hypothalamus and pituitary, inhibiting gonadotropin secretion and potentially causing azoospermia. 6, 1, 3

Additional cautions:

• Do not reassure patients that FSH of 10-12 is "completely normal" without semen analysis—this level warrants investigation even if some men remain fertile 1
• Lifestyle factors including smoking, poor diet, and environmental exposures may temporarily affect FSH levels 3, 2
• If semen analysis reveals severe oligospermia (<5 million/mL) or azoospermia with FSH >7.6 IU/L, proceed with karyotype analysis and Y-chromosome microdeletion testing 1, 3

Treatment Considerations if Fertility is Impaired

If semen analysis confirms abnormal parameters:

• For idiopathic infertility with FSH <8 IU/L, FSH analogue treatment may improve sperm concentration, pregnancy rate, and live birth rate, though this is off-label use 6, 1
• Selective estrogen receptor modulators (clomiphene, tamoxifen) or aromatase inhibitors may be considered for low testosterone with elevated FSH, though benefits are small and outweighed by assisted reproductive technology options 6, 1
• Supplements and antioxidants have questionable clinical utility with no clear reliable data supporting their use 6, 3

Prognosis and Realistic Expectations

The statement that "plenty of men with FSH 10-12 have perfectly normal testosterone and father children naturally" is clinically accurate but requires nuance:

• This represents biological variation at the upper end of normal rather than the typical pattern 1, 2
• FSH levels >7.6 IU/L are associated with non-obstructive azoospermia and testicular dysfunction as a population trend, though individual variation exists 1
• Up to 50% of men with non-obstructive azoospermia may still have retrievable sperm, demonstrating that even higher FSH doesn't preclude all reproductive potential 1

The appropriate clinical approach is to confirm fertility status through semen analysis rather than assuming normalcy based on FSH and testosterone levels alone, while avoiding testosterone supplementation that would definitively impair spermatogenesis. 1, 3