Does Sperm Volume Decrease with Age?
Yes, semen volume consistently decreases with advancing male age, beginning as early as the mid-30s and continuing progressively throughout life. 1, 2, 3
Evidence for Age-Related Decline in Semen Volume
The most robust evidence demonstrates a clear, continuous decline in semen volume with age:
Semen volume decreases by approximately 0.03 ml per year of age in healthy men, with this decline occurring continuously between ages 22-80 years without evidence of a threshold. 3
Men over age 52 have significantly lower semen volumes (mean 1.8 ml) compared to younger men under 52 (mean 3.2 ml), representing a 44% reduction. 1
The decline begins after age 34, with ejaculate volume specifically falling after age 45 in a large cohort analysis of 4,822 semen samples. 2
Middle-aged men (>45 years) have smaller semen volumes (2.5±1.4 ml) compared to young men (<35 years) (3.2±1.5 ml), a statistically significant difference. 4
Additional Age-Related Changes Beyond Volume
While semen volume declines, other parameters are also affected:
Total sperm output decreases significantly (median 74 million vs 206 million sperm per ejaculate in older vs younger men), though sperm concentration (density) remains relatively preserved. 1
Sperm motility declines by 0.7% per year, with progressive motility decreasing by 3.1% per year and total progressively motile sperm count falling by 4.7% per year. 3
After age 30, sperm motility and progressive motility decline consistently, with total sperm numbers declining immediately after age 34. 2, 5
Sperm morphology deteriorates, with older men showing fewer normal forms (14% vs 25%) and reduced vitality (51% vs 80%). 1
Clinical Implications
The 2021 AUA/ASRM guidelines emphasize that clinicians should advise couples with advanced paternal age (≥40 years) that there is an increased risk of adverse health outcomes for their offspring, including increased de novo mutations, sperm aneuploidy, and genetically-mediated conditions. 6
Advanced paternal age increases sperm DNA fragmentation, with men aged ≥40 years having significantly higher DNA fragmentation index than those <40 years across all cohorts. 5
Important Caveats
The decline in semen volume is continuous and progressive, not threshold-based, meaning fertility potential gradually diminishes rather than dropping suddenly at a specific age. 3
While semen volume and total sperm output decline, sperm concentration (sperm per ml) may remain relatively stable or even increase slightly, suggesting the testes compensate by producing more concentrated ejaculates. 1, 2
Individual variation exists, and these are population-level trends—some older men maintain excellent semen parameters while some younger men have poor parameters. 1