5 ms·

The Sperm-Count ‘Crisis’ Doesn’t Add Up

18 points by elsewhen 5y ago

koheripbal 5y ago
summary: This article contains a lot of speculation, but none of it contradicts the evidence that sperm counts have dropped. I makes the argument that that might not reduce fertility as much as other scientists assume, and so we don't really know if there's an actual crisis happening.
- carlmr 5y ago
  Not quite true, they also say that counting sperm is difficult and the methods were slowly refined. So early studies might suffer from systematic error. Maybe a job for this company that was posted on HN which has an app for counting stuff.
  - guessbest 5y ago
    Do you mean something like Uber for Sperm?
randomopining 5y ago
Def from nano plastics.
- alunchbox 5y ago
  I'd look at stress indicators first. Nano plastics have a lot of issues, but it's not a silver bullet. We live in a world where most people are constantly stressed out. First hand I've seen stress cause physical changes. Never realized how bad it can get.
  - tuatoru 5y ago
    Stress maybe; sedentism definitely. The sperm decline coincides with the decline in male jobs which involved being on your feet as a proportion of total jobs.
    - fiftyfifty 5y ago
      Lower sperm counts as well as lower testosterone levels in men have definitely been associated with obesity, and there's no question that's a problem these days.
    - torstenvl 5y ago
      Don't those seated office jobs also weaken the relationship between work done and results achieved? And make shifting internal politics a major factor in advancement? Feeling ineffectual and not knowing who you can trust seem like pretty major stressors to me.
  - missedthecue 5y ago
    Less stressed then before? I don't need to put a harvest in the ground to avoid starvation next winter. I don't need to worry about the neighboring tribe burning down my village and murdering me. I haven't lost 6 children in childbirth. I wouldn't be surprised if humans have fewer real stressors than ever.
- atatatat 5y ago
  Estrogen emitters, endocrine disrupting junk including plastics, hops, receipt paper, and tons of other everyday items and foods. Lack of True Rest//Recovery. Stress//clinical symptoms of anxiousness, caused or worsened by the above.
  - refurb 5y ago
    5G should be added to your list. Definitely 5G
Analemma_ 5y ago
This debunking... really isn't. To pick a random example: > For starters, no one knows what an “optimal” sperm count is. The World Health Organization sets a range of “normal” sperm count as from 15 to 250 million sperm per milliliter. (Men produce about 2 to 5 milliliters of semen per ejaculation.) But it isn’t clear that more is better. Above a certain threshold — 40 million per milliliter, according to the W.H.O. — a higher sperm count does not mean a man is more fertile. It doesn't follow from this that there is no sperm-count crisis. Since the marginal energy cost of more sperm is pretty small, you'd expect that evolution would build a generous safety margin on the sperm count required to achieve reproduction, and we can be in a "crisis" if we're shrinking that safety margin even if it hasn't reached zero yet. e.g, suppose the threshold is 25MM/mL and a "normal" count is 100MM/mL; a decrease to 40MM/mL can be a crisis even if it hasn't had any visible effects yet. Not to mention that whole paragraph completely disregards the possibility that falling sperm counts are as much a symptom of declining health as a cause of problems unto themselves.
- chakkepolja 5y ago
  > Not to mention that whole paragraph completely disregards the possibility that falling sperm counts are as much a symptom of declining health as a cause of problems unto themselves. Could this be a symptom of more stressful lifestyle in particular?
pengaru 5y ago
"When I started looking at phthalates, around 2000, phthalate syndrome had been shown experimentally in rodents but not in humans. Mother rats given phthalates had male babies with a smaller penis and scrotum, their sperm counts were lower and their AGD was shorter. I ran a study where we measured the stored urine of pregnant women for phthalates and we measured their male babies’ and toddlers’ AGDs – a first – along with some other genital measurements. We found exactly what had been found in rodents: phthalate syndrome. I then did a study of college-age men, where we got them to give a semen sample and measured their AGD, and we showed that the shorter the AGD, the lower the sperm count. This is why I am confident: we have a direct link from phthalates to short AGD and then from short AGD to low sperm count, and those results have been confirmed by subsequent studies." From https://www.theguardian.com/society/2021/mar/28/shanna-swan-fertility-reproduction-count-down https://www.theguardian.com/society/2021/mar/28/shanna-swan-...

18 points by elsewhen 5y ago

summary: This article contains a lot of speculation, but none of it contradicts the evidence that sperm counts have dropped. I makes the argument that that might not reduce fertility as much as other scientists assume, and so we don't really know if there's an actual crisis happening.

carlmr 5y ago
Not quite true, they also say that counting sperm is difficult and the methods were slowly refined. So early studies might suffer from systematic error. Maybe a job for this company that was posted on HN which has an app for counting stuff.
- guessbest 5y ago
  Do you mean something like Uber for Sperm?

randomopining 5y ago

Def from nano plastics.

alunchbox 5y ago
I'd look at stress indicators first. Nano plastics have a lot of issues, but it's not a silver bullet. We live in a world where most people are constantly stressed out. First hand I've seen stress cause physical changes. Never realized how bad it can get.
- tuatoru 5y ago
  Stress maybe; sedentism definitely. The sperm decline coincides with the decline in male jobs which involved being on your feet as a proportion of total jobs.
  - fiftyfifty 5y ago
    Lower sperm counts as well as lower testosterone levels in men have definitely been associated with obesity, and there's no question that's a problem these days.
  - torstenvl 5y ago
    Don't those seated office jobs also weaken the relationship between work done and results achieved? And make shifting internal politics a major factor in advancement? Feeling ineffectual and not knowing who you can trust seem like pretty major stressors to me.
- missedthecue 5y ago
  Less stressed then before? I don't need to put a harvest in the ground to avoid starvation next winter. I don't need to worry about the neighboring tribe burning down my village and murdering me. I haven't lost 6 children in childbirth. I wouldn't be surprised if humans have fewer real stressors than ever.
atatatat 5y ago
Estrogen emitters, endocrine disrupting junk including plastics, hops, receipt paper, and tons of other everyday items and foods. Lack of True Rest//Recovery. Stress//clinical symptoms of anxiousness, caused or worsened by the above.
- refurb 5y ago
  5G should be added to your list. Definitely 5G

Analemma_ 5y ago

This debunking... really isn't. To pick a random example: > For starters, no one knows what an “optimal” sperm count is. The World Health Organization sets a range of “normal” sperm count as from 15 to 250 million sperm per milliliter. (Men produce about 2 to 5 milliliters of semen per ejaculation.) But it isn’t clear that more is better. Above a certain threshold — 40 million per milliliter, according to the W.H.O. — a higher sperm count does not mean a man is more fertile. It doesn't follow from this that there is no sperm-count crisis. Since the marginal energy cost of more sperm is pretty small, you'd expect that evolution would build a generous safety margin on the sperm count required to achieve reproduction, and we can be in a "crisis" if we're shrinking that safety margin even if it hasn't reached zero yet. e.g, suppose the threshold is 25MM/mL and a "normal" count is 100MM/mL; a decrease to 40MM/mL can be a crisis even if it hasn't had any visible effects yet. Not to mention that whole paragraph completely disregards the possibility that falling sperm counts are as much a symptom of declining health as a cause of problems unto themselves.

chakkepolja 5y ago
> Not to mention that whole paragraph completely disregards the possibility that falling sperm counts are as much a symptom of declining health as a cause of problems unto themselves. Could this be a symptom of more stressful lifestyle in particular?

pengaru 5y ago

"When I started looking at phthalates, around 2000, phthalate syndrome had been shown experimentally in rodents but not in humans. Mother rats given phthalates had male babies with a smaller penis and scrotum, their sperm counts were lower and their AGD was shorter. I ran a study where we measured the stored urine of pregnant women for phthalates and we measured their male babies’ and toddlers’ AGDs – a first – along with some other genital measurements. We found exactly what had been found in rodents: phthalate syndrome. I then did a study of college-age men, where we got them to give a semen sample and measured their AGD, and we showed that the shorter the AGD, the lower the sperm count. This is why I am confident: we have a direct link from phthalates to short AGD and then from short AGD to low sperm count, and those results have been confirmed by subsequent studies." From https://www.theguardian.com/society/2021/mar/28/shanna-swan-fertility-reproduction-count-down https://www.theguardian.com/society/2021/mar/28/shanna-swan-...