The Y chromosome degrades over time and men's health is paying for it

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The Y chromosome can disappear over time in human males, which may introduce a number of health problems. While the exact trigger for such degeneration is unknown, environmental factors can play a significant role. New research on the topic hints that the human Y chromosome is evolutionarily unstable and could even become extinct in the future.

Chromosomal complications

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Specifically, the loss of the Y chromosome (LOY) has “important effects in shaping the activity of the immune system,” and can open the door wider for several diseases, including “cancer, neurodegeneration, cardiovascular disease and acute infection,” said a January 2025 study published in the journal Nature Reviews Genetics. “If you’re a male, you do not want to lose your Y chromosome, it’s definitely going to shorten your life,” Kenneth Walsh, a professor at the University of Virginia, said to New Scientist.

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When it comes to cancer, “tumors without the Y chromosome grew twice as fast as those with it,” said New Scientist. This is largely because the “loss of the Y chromosome causes tumor cells to make proteins that exhaust T cells, a kind of immune cell that ordinarily recognizes and attacks cancers.” In addition, research has shown that the risk of Alzheimer’s disease greatly increases with LOY. Experts speculate that the “Y chromosome-deficient immune cells infiltrate the brain and may lead to increased inflammation or may be less able to regulate the inflammatory response,” a symptom which is “characteristic of Alzheimer’s disease,” the study said.

Micro mistakes

Y chromosome loss is largely “due to cell division mistakes,” said News Medical. This is “enormously common” and “not like some freakish accident,” Lars Forsberg, a senior lecturer and associate professor at Uppsala University in Sweden, said to New Scientist. It likely happens to all males, but age increases the level of loss significantly. Additionally, there is “no data to suggest that men with loss of Y would feel it.”

LOY is “increasingly viewed as a marker of genome instability and a biological indicator of environmental stress,” said News Medical. It could also be a major reason why females tend to have longer lifespans. “Females seem to be the stronger sex from a genetic point of view, with a more stable and less disease-prone genome,” said the study. While the Y chromosome degrades on the individual level, there is evidence that the chromosome may be going extinct on an evolutionary scale as well.

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