Overview
- Oxford researchers, whose cross-species meta-analysis appeared Wednesday in Proceedings of the Royal Society B, combined 115 human studies with 56 animal studies to test how in-body sperm storage affects quality.
- In men, longer gaps between ejaculations were tied to more DNA damage and oxidative stress with lower motility and viability, and the authors described the effects as statistically significant but modest.
- The team did not see consistent drops in fertilization or embryo quality in humans, while animal studies more often linked longer storage to fewer fertilizations and poorer embryos.
- The authors said the World Health Organization’s two-to-seven-day abstinence guidance may need review, noting reports that ejaculating within 48 hours can improve IVF results.
- Across many species, females preserved stored sperm better through antioxidant-rich storage organs, a pattern that could inspire improvements in assisted reproduction and conservation breeding.