19/11/2025
🤰🏼A major new genetic study has revealed why children of older fathers face higher risks of inherited diseases.
Researchers at the Wellcome Sanger Institute found that as men age, a growing number of “selfish” s***m stem cells outcompete their healthy counterparts—causing disease-causing mutations to multiply rapidly rather than gradually.
By sequencing over 100,000 s***m cells from 81 men aged 20 to 70, scientists discovered that while men in their early 30s had about 1 in 50 s***m carrying harmful mutations, that figure rose to nearly 1 in 20 by age 70. These mutations occur in at least 40 genes that make s***m stem cells divide faster, creating more mutated s***m as men get older.
Unlike random genetic errors, these “selfish mutations” boost cell growth in the te**es, but at a cost: they’re linked to serious neurodevelopmental disorders, including autism, and even certain cancers.
The study also found that s***m accumulate mutations much more slowly than other cells in the body and seem shielded from environmental factors like smoking or alcohol. Still, the exponential rise in selfish mutations with age suggests that paternal age plays a far greater role in offspring health than previously recognized.
Experts now urge that both men and women consider age when planning families—since older fathers, not just older mothers, contribute significantly to genetic risks passed to future generations.
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📄 RESEARCH PAPER
📌 Neville, M.D.C., Lawson, A.R.J., Sanghvi, R. et al. S***m sequencing reveals extensive positive selection in the male germline. Nature (2025).
