RFK Jr.'s warnings about sperm counts fuel doomsday claims about male fertility

It’s not uncommon for Health and Human Services Secretary Robert F. Kennedy Jr.

It’s not uncommon for Health and Human Services Secretary Robert F. Kennedy Jr. to mention sperm counts when he makes a public appearance.

In recent television interviews, political speeches and congressional hearings, Kennedy has repeatedly claimed that teenage boys today have half the sperm that men in their 60s do — a stat that’s not exactly accurate. Kennedy has cited the talking point as evidence of a broader health crisis in the U.S.

“We have fertility rates that are just spiraling. A teenager today, an American teenager, has less testosterone than a 68-year-old man. Sperm counts are down 50%,” he told Fox News’ Jesse Watters in April, adding: “It’s an existential problem.”

Contrary to Kennedy’s claims, sperm counts decline with age, so young men have much higher counts than older men. And data about sperm counts in teen boys largely does not exist.

Some researchers contend that men’s overall sperm counts are lower than they were generations ago, based mostly on two papers published in the last decade. Others say there’s no convincing evidence of the trend. And many agree that even if sperm counts are declining, it does not amount to a full-blown fertility crisis.