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Counterargument is that the global sperm count decline is global. As in not limited to humans. It is seen in many mammals.

akovaski 3y ago
Do you have a source for the claim that sperm count for many mammals has been declining? I was only able to find "Sperm counts in semen of farm animals 1932-1995" https://pubmed.ncbi.nlm.nih.gov/9401823/ https://pubmed.ncbi.nlm.nih.gov/9401823/ Which states that farm animal sperm count has unchanged or has increased over time.
dmurray 3y ago
Even the evidence for humans is a bit patchy - a third of studies come to the opposite conclusion, and plenty of those that agree have massive methodological flaws. So I doubt we can say that with any real confidence for other mammals. https://www.astralcodexten.com/p/declining-sperm-count-much-more-than https://www.astralcodexten.com/p/declining-sperm-count-much-...
- trhway 3y ago
  Just want to highlight that you put a blog named "Astral Codex Ten" claiming patchiness and methodological flaws because "data are very noisy" against the peer-reviewed journals like Oxford Scientific which for example states: "This comprehensive meta-regression analysis reports a significant decline in sperm counts (as measured by SC and TSC) between 1973 and 2011, driven by a 50–60% decline among men unselected by fertility from North America, Europe, Australia and New Zealand. " If the "data are very noisy" argument were a sound argument it would have dismissed most of the science that we have today.
  - dmurray 3y ago
    I'm not putting anything against anything. That paper [0] completely agrees with the blog - they threw out all but 38 of the 2936 studies they considered, for crying out loud - and neither makes any call on sperm count in animals other than humans. [0] https://academic.oup.com/humupd/article/29/2/157/6824414 https://academic.oup.com/humupd/article/29/2/157/6824414

akovaski 3y ago

Do you have a source for the claim that sperm count for many mammals has been declining? I was only able to find "Sperm counts in semen of farm animals 1932-1995" https://pubmed.ncbi.nlm.nih.gov/9401823/ https://pubmed.ncbi.nlm.nih.gov/9401823/ Which states that farm animal sperm count has unchanged or has increased over time.

dmurray 3y ago

Even the evidence for humans is a bit patchy - a third of studies come to the opposite conclusion, and plenty of those that agree have massive methodological flaws. So I doubt we can say that with any real confidence for other mammals. https://www.astralcodexten.com/p/declining-sperm-count-much-more-than https://www.astralcodexten.com/p/declining-sperm-count-much-...

trhway 3y ago
Just want to highlight that you put a blog named "Astral Codex Ten" claiming patchiness and methodological flaws because "data are very noisy" against the peer-reviewed journals like Oxford Scientific which for example states: "This comprehensive meta-regression analysis reports a significant decline in sperm counts (as measured by SC and TSC) between 1973 and 2011, driven by a 50–60% decline among men unselected by fertility from North America, Europe, Australia and New Zealand. " If the "data are very noisy" argument were a sound argument it would have dismissed most of the science that we have today.
- dmurray 3y ago
  I'm not putting anything against anything. That paper [0] completely agrees with the blog - they threw out all but 38 of the 2936 studies they considered, for crying out loud - and neither makes any call on sperm count in animals other than humans. [0] https://academic.oup.com/humupd/article/29/2/157/6824414 https://academic.oup.com/humupd/article/29/2/157/6824414