Comment by alexandercrohde | Hacker News Reader

Comment by alexandercrohde | Hacker News Reader

alexandercrohde

Summary (though I highly recommend reading this)

1. Men's sperm counts have gone down by half in the last 30 years in industrialized countries, nobody has established why. [A]

2. The environment is full of (>1,400) endocrine-disrupting chemicals that may be an answer. One such example is Atrazine.

3. "We examined two doses of ATZ which included the 'safe' level for drinking water, determined by the Australian government, as well as a 10-fold higher dose delivered to the mice in drinking water from weaning until 12 weeks of age,"

4. "Our results showed significant effects on the reproductive and general health of male mice." Including reduced sperm count.

5. Interestingly, "We found a change in gene expression in the liver following ATZ exposure. Two genes implicated in fat uptake were found to be over-expressed, an early stage of 'fatty liver disease,"

6. Lower doses over a long exposure time may potentially do more damage than a high dose.

7. This study has been accepted for publication last month. The pair is continuing to do more research.

-- [A] - https://www.scientificamerican.com/article/sperm-count-dropp...

RE: safe levels and the sheer number of chemicals flooding into the environment, I wonder whether in some cases a given chemical studied in isolation could be safe at a given level, yet have unexpectedly strong negative effects when combined with the presence of other chemicals -- also perhaps at or below their respective "safe" levels that were determined by studying them in isolation.

As countries become more wealthy and educated, they use more endocrine disrupting chemicals and thus have lower birth rates.

I think that one is a lot tougher to prove causation with, especially because in the article it says the EU banned Atrazine, yet they all have falling birth rates as well. I think that one has more to do with higher education and income.

There are confounding co-factors to birth rate in advanced economies. it would be grossly simplistic to ascribe the birth rate to falling sperm motility levels, when advanced societies offer IVF and assisted reproduction often on the public purse.

I suspect the economics here are stronger than biology: it is too expensive to raise and (privately) educate children and in the developed economies, familys delay childbirth into later years and so tend to have less children.

TL;DR I believe the birth rates in Africa and Asia are varying more as a function of economy, than of insecticide.

"Men's sperm counts have gone down by half in the last 30 years in industrialized countries"

The bad is that this probably extends to other health problems too, besides sperm count.

Otherwise, as this fun comic/charge[1] shows, would not be that a big problem for everyone.

1- https://dilbert.com/strip/2014-04-05

:last addition: Sperm swimming speed is probably affected as well.

Reply on news.ycombinator.com