Young cancer survivors are losing the Y chromosome in their sperm—a glitch you usually only see in the blood of the very old.
March 24, 2026
Original Paper
High prevalence of loss of Y chromosome in the spermatozoa of young cancer survivors
medRxiv · 10.64898/2026.03.20.26348822
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The Takeaway
Loss of the Y chromosome is a classic hallmark of aging, but finding it in the reproductive cells of young men is a major first. It reveals that cancer treatments can trigger specific 'aging' signatures in the male germline, potentially impacting the health of future children.
From the abstract
Cancer-related genomic instability (GI) may cause genetic alterations in spermatozoa, implying health issues not only in cancer survivors, but also in their children [1, 2]. We therefore studied Loss of Y chromosome (LOY), considered as hallmark of GI [3-15], in spermatozoa and blood from survivors of childhood and testicular cancer (CC, TC), and controls (CTRL). We found that LOY was statistically significantly more frequent in spermatozoa from cancer survivors than in controls (Odds Ratio [OR]