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It would be interesting to see a comparison across continental ancestry groups. In particular, are heat-adapted groups (e.g. Africans) less susceptible to sperm damage from high temperatures than cold-adapted groups (e.g. Finns?) Depending on the answer, such results could then be used to interpret the overall decline in sperm. If Africans are indeed resistant and it's mainly heat, it should turn out that African-American men have shown less of a decline in sperm quality than Europeans. If African-American sperm quality has diminished to a similar degree to other groups, despite Africans being less susceptible to heat damage, then we know that while heat can be a factor, it isn't the actual factor at play.

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Interesting that the number 1 reason for men’s testosterone decline is felling defeated. Since testosterone is critical for a man’s sperm production and his sense of manly courage, it makes sense that wherever feminism takes root, men’s testosterone, fertility, and manliness greatly suffer.

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"Decreases in the percentage of sperm with normal histone-protamine substitution (78.7 ± 4.5 versus 69.0 ± 4.1), chromatin condensation (70.7 ± 4.7 versus 63.6 ± 3.3) and mitochondrial function (76.8 ± 4.9 versus 54.0 ± 6.1) were also evident at T1, and strong parallel up-regulation of genes involved in response to heat stress and hypoxia was found."

"Both groups showed a reversible increase in the proportion of spermatozoa with a disrupted MMP (both p < 0.05 when the minimums were compared with baseline levels, the same below), sperm apoptosis (both p < 0.01) and high DNA stainability (both p < 0.05)."

Did you find anything on noticeable effects from having a dad that likes using the sauna? If there are negative effects when children actually are conceived, this may dissuade men from using heat-based contraception.

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I didn't look. That would be a weak study design. One would have to use sibling control, but who has that kind of data...

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Is it a coincidence this was published 15 minutes after this: https://stuartritchie.substack.com/p/testosterone?s=r

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Apr 25, 2022·edited Apr 25, 2022Author

Yep! I just posted mine and saw his afterward. That's hilarious, but our reasons for posting are different. He was sent some Tucker Carlson material, and he was checking the science on that.

Someone sent me the Finnish study, and I had read it before, but decided to check out if there were any replications. That literature review become this post.

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literally bruh moment. sorry to say it

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Is there a sperm shortage in Africa or Mexico?

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Mexico has below replacement TFR. The example you're looking for is the genocidal state of Israel.

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