26/03/2026
π¬ WHO tells men to abstain for 2 to 7 days before giving a s***m sample for fertility treatment. A new Oxford study says that advice may be doing more harm than good.
Researchers at the University of Oxford conducted a sweeping meta-analysis of 115 human studies covering nearly 55,000 men, combined with 56 studies across 30 non-human animal species. Their conclusion is striking: s***m sitting in storage, whether inside the male body during abstinence or inside the female reproductive tract, ages and deteriorates rapidly in a process they call post-meiotic s***m senescence.
In men, longer abstinence periods were directly linked to more DNA damage in s***m, higher oxidative stress, and measurable declines in s***m motility and viability. The damage happens because s***m cells are uniquely vulnerable. They burn through their energy reserves quickly, carry almost no protective cytoplasm, and have very little capacity to repair themselves. The longer they sit waiting, the worse they get.
Crucially, the decline in s***m quality happened regardless of how old the man was. S***m ages on its own clock, independent of the person producing it. The same deterioration pattern was observed across the animal kingdom, from fruit flies to mammals, with reduced fertilization success and poorer embryo quality as direct consequences.
The study did find one notable exception. Females, across species, appear to be better at preserving stored s***m. Their specialized storage organs seem to actively nourish and protect s***m using antioxidants, something that evolution has fine-tuned over millions of years and that researchers think could inspire better artificial s***m storage technology.
The takeaway for fertility medicine is clear: more frequent ej*******on, not extended abstinence, produces healthier s***m.
π RESEARCH PAPER
π Sanghvi et al, "S***m storage causes s***m senescence in human and non-human animals", Proceedings of the Royal Society B (2026)