We all know getting older changes our bodies — but few realize it can also change your DNA.
Scientists from King’s College London have discovered that as men age, their sperm quietly mutates, increasing the risk of passing on diseases to their children. “We expected changes,” said Dr. Matthew Neville, “but we didn’t realize how much age drives up dangerous mutations.”

By their 30s, about 2% of sperm carries potential disease-causing changes. By age 70, that number doubles. Experts say it’s a hidden genetic risk many older fathers never think about. “Some mutations don’t just survive,” explained Professor Matt Hurles. “They actually thrive — giving unhealthy sperm an edge over healthy ones.”
The findings don’t mean older men shouldn’t have kids — just that nature plays a more complicated game than we once thought.
It’s a quiet reminder that time shapes everything, even the parts of us we never see.