This claim is misleading because the approximately 52% decline was reported over roughly 45 years, from 1973 to 2018, not over the last 25 years.
Misleading
Male sperm counts are down 52% in the last 25 years.
Humans could face reproductive crisis as sperm count declines, study finds - Fertility problems | The Guardian
Source: theguardian.com
At a glance
Verified August 15, 2026Key Evidence
The primary 2022 review in Human Reproduction Update reports a decline from approximately 101.2 million to 49.0 million sperm per milliliter between 1973 and 2018, or about 51.6% over roughly 45 years.
The Guardian and CNN independently report the same approximate magnitude and period.
Some researchers, as summarized by Scientific American, dispute whether the available evidence is sufficient to conclude that semen quality is deteriorating worldwide, so the exact scope of the trend remains debated.
The reporting
What the Evidence Shows
The underlying finding is broadly supported, but the timeframe in the claim is materially inaccurate.
A 2022 systematic review and meta-regression published in Human Reproduction Update estimated that average sperm concentration declined from about 101.2 million sperm per milliliter in 1973 to about 49.0 million per milliliter in 2018, a decrease of approximately 51.6%. This is a global estimate covering samples collected over about 45 years, not 25 years.
The Guardian and CNN accurately summarize the 2022 review as finding an approximately 52% decline between 1973 and 2018. Their reporting supports the magnitude of the decline, but not the statement that it occurred within the last 25 years.
Earlier reporting on the 2017 study described a decline of more than 50% across approximately four decades, particularly among men in North America, Europe, Australia, and New Zealand. That evidence also does not establish a 52% decline specifically during a 25-year period.
The broader interpretation remains debated. Scientific American cites research arguing that available data do not establish a worldwide deterioration in semen quality with certainty, while the 2022 review reports a substantial global downward trend. Differences in study populations, laboratory methods, geographic coverage, and sampling make the exact size and universality of the decline uncertain.
Therefore, a more accurate version would be: “A major 2022 review estimated that average sperm concentration fell by about 52% worldwide between 1973 and 2018.”
Primary trail
Verified Sources10
Open source