Health · Medical Research · 2 hrs ago
Studies differ on whether sperm counts are falling worldwide
A 2022 analysis estimated that sperm concentration fell about 52% worldwide between 1973 and 2018, while total sperm count fell about 62%.
It combined 223 studies of more than 57,000 men in 53 countries who were not selected based on fertility.
A 2025 review of US studies found no overall change in sperm concentration in its initial analysis of 58 studies involving 11,787 men without known infertility issues.
After accounting for geographic region and fertility status, those researchers found a modest annual decline.
The findings differ, so the global trend is not clear-cut; the studies cover different groups and use different analyses.
Sperm concentration is the number of sperm per milliliter of semen, while total count measures the number in an entire ejaculate.
The numbers do not show that men are headed toward being unable to reproduce, and the available findings do not settle what is happening everywhere.
A 2022 global analysis estimated that sperm concentration fell by 51.6% and total sperm count by 62.3% between 1973 and 2018.
The analysis combined 223 studies involving more than 57,000 men from 53 countries.
A 2025 review found no overall change in sperm concentration in samples from American men collected between 1970 and 2018.
After accounting for geographic region and fertility status, the 2025 review found a modest annual decline.
The findings differ, and the article says other research raises questions about whether the same decline is happening everywhere.
- Who
- Researchers studying sperm counts, and men concerned about fertility.
- What
- Studies differ on whether sperm counts have fallen worldwide.
- When
- The studies cover samples collected from 1970 through 2018; the analyses were published in 2022 and 2025.
- Where
- The 2022 analysis covered men from 53 countries; the 2025 review covered American men.
- Why
- Researchers and patients are concerned about possible effects on fertility and men’s health.
2022 global analysis
2025 review of American men
Overall trend
2022 global analysis
Estimated average sperm concentration fell 51.6% and total sperm count fell 62.3% between 1973 and 2018.
2025 review of American men
Found no overall change in sperm concentration in its initial analysis of samples collected from 1970 through 2018.
Adjusted findings
2022 global analysis
Not stated.
2025 review of American men
After adjustments for geographic region and fertility status, found a modest annual decline.
Scope
2022 global analysis
Combined 223 studies involving more than 57,000 men from 53 countries.
2025 review of American men
Covered 58 studies involving 11,787 American men without known infertility issues.
Samples later assessed in a 2025 review were collected from American men.
Samples included in a 2022 global analysis were used to estimate changes in sperm concentration and total sperm count.
A global analysis estimated declines in sperm concentration and total sperm count.
A review and meta-analysis found no overall change in sperm concentration in its initial analysis of American samples.
CNN published Dr. Jamin Brahmbhatt’s article examining why the findings are complicated.
- 2022 global analysis
- 223 studies; more than 57,000 men; 53 countries
- Estimated sperm concentration change
- Fell 51.6% between 1973 and 2018
- Estimated total sperm count change
- Fell 62.3% between 1973 and 2018
- 2025 US review
- 58 studies; 11,787 American men without known infertility issues
- Adjusted 2025 finding
- Modest annual decline in sperm concentration
What people are saying
are sperm counts really dropping worldwide?
could sperm measurements give a window into a man’s overall health?
Sources
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