Is US health secretary's claim of teen sperm decline correct?
12 May 2026

United States Health Secretary Robert F. Kennedy Jr. has described the country's declining birth rate as an "existential crisis."

Speaking at a White House event on maternal healthcare on Monday, he warned that this crisis threatens not only the economy but also national security.

He claimed teenage boys today have a lower sperm count than nearly 70-year-old men did in the 1970s.

But how correct is his claim?

Kennedy blames environmental, health factors for fertility crisis
Crisis causes

Kennedy blamed a combination of environmental and health factors for the fertility crisis.

He mentioned obesity, metabolic disorders, endocrine disruptors, pesticides, and a "toxic soup" as contributors to declining reproductive health.

His department is investigating how these exposures may be affecting fertility outcomes.

The fertility crisis for women started around 2007, according to Kennedy.

Sperm counts have declined over decades, but specifics are unclear
Claim scrutiny

Kennedy's claim is based on a 2022 global review published in Human Reproduction Update, which found significant declines in sperm counts over decades.

However, the study didn't specifically compare modern American teenagers to men in the 1970s as Kennedy suggested.

Some reproductive health experts agree that sperm decline is worth studying, but caution against concluding long-term trends due to varying methodologies and standards across decades.

Debate continues over implications of declining sperm counts
Ongoing debate

The issue of declining sperm counts remains a subject of debate among experts.

Dolores Lamb, a researcher at Weill Cornell Medicine, called the hypothesis of global sperm count decline "an important hypothesis" but said the data isn't good enough to conclude.

Despite this uncertainty, Kennedy continues to use these statistics as evidence for America's fertility crisis.