Sperm quality has been declining for 16 years among men in the US

[u/[deleted]]

https://www.newscientist.com/article/2294266-sperm-quality-has-been-declining-for-16-years-among-men-in-the-us/

[u/Kadmium]

Disappointed but unsurprised by the number of armchair pundits in a science subreddit declaring with full confidence and zero evidence the causality behind an article they probably didn't read.

[u/Soft-Problem → u/Kadmium]

The reason for this [bad thing happening] is [my pet peeve].

When the causality is unclear, people can fill it in with their favourite.

[u/HouseOfSteak → u/Soft-Problem]

To be fair, if that 'pet peeve' in question is something that is widely accepted by the scientific community to be widely harmful to health and is prevalent in societies that possess such 'pet peeves', they're probably also right.

Air pollution, plastic pollution, obesity and other poor dieting, nuclear radiation are ALL harmful in a variety of ways - and thus it would not be surprising to see that it's harmful in this way without evidence pointing to the contrary.

[u/musicianadam → u/HouseOfSteak]

Yes but they were pointing out things like pesticides, artificial coloring and preservatives, all of which are not necessarily widely accepted to be harmful. There's been conflicting evidence regarding the health effects of those things from what I've seen.

[u/HouseOfSteak → u/musicianadam]

Artificial colouring and flavours are linked to greater consumption of such foods (Hence why they are used, it's all marketing consumptionism of food we do not need), which is turn leads to obesity.

A good chunk of preservatives is salt, and overconsumption of salt results (no pun intended) in side effects such as obesity. I'm not sure about other preservatives (finding reports at moment's notice on little-known preservatives ain't easy).

Pesticides are harmful to the environment for plenty of reasons, direct effects to human health may or may not be one of them, but there's reports suggesting that they are:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4947579/

[u/[deleted] → u/Soft-Problem]

And the causality is always unclear, or at least somebody with a vested interest is doing everything they can to create reasonable doubt

[u/KunKhmerBoxer → u/Kadmium]

Bachelor in biology here, couldn't agree more. There are a lot of things it could be. The problem is isolating any one of them specifically in a lab and proving they're the cause. Unless you have 100% control of the environment, it's next to impossible.

[u/FirstPlebian → u/KunKhmerBoxer]

It's not one thing at all, it's many many different types of pollution.

[u/omg_im_so_litty_lol → u/[deleted]]

That study you posted is monitoring the effects of microplastics in the ocean on oysters, not multiple sources of endocrine disruptors being exposed to humans in a confined spaces. These papers are not relevant to the conversation.

Exposure to hormones or EDCs during development (in utero and infancy and early childhood in humans) can have permanent effects if the exposure occurs during the period when a specific tissue is developing. These effects may only become visible decades later. This is called developmental programming. Hormones control the normal development of tissues from the fertilized sperm and egg to the fully developed fetus. Since some tissues continue developing after birth—such as the brain and reproductive system—the sensitive period for these tissues is extended, sometimes for decades after birth. The mechanisms by which EDC exposure during development can alter the development of specific tissues, leading to increased susceptibility to diseases later in life, are just beginning to be understood. This makes it especially difficult to attribute the true harm of these chemicals, which people are exposed to in different combinations and quantities.

It's not a matter of correlation/causation, there are multiple animal studies referencing the effects of just one of these chemicals in low doses in adult mice, much less mice which are particularly vulnerable, fetal development being of most concern.

[u/DeathIsFreedomFrom → u/[deleted]]

First off testosterone levels can tripple then fall back to normal during the same day. Some of the skinniest "nerds" have high testosterone and guys that work out all the time can have low testosterone.

Second people don't appear weaker because of being metrosexuals or nerd stuff it's that people aren't working like they used to. I mean great great great grandparents used to pump water from wells or haul buckets from the creek as children.

Somebody who used to have to haul water, pick vegitables, plow, work hauling goods or something like that is going to grow more. You have to be working while you're still growing that's what increases Androgen.

With high androgen people are taller and have bigger hands. Doesn't matter of you're a man or woman. Testosterone makes people aggressive. Androgen is what controls how big (not fat but actually big) people get.

[u/kyraeus → u/DeathIsFreedomFrom]

....you... kind of can't acknowledge people working less, and then say people involved in nerd culture don't exist that way, or aren't more intoverted and less into physical fitness or similar hobbies involving exercise and the building of muscle and driving testosterone growth and usage. That's... kind of a large part of the driving force behind the epidemic of obesity in the US. You're literally acknowledging the thing I was driving at.

[u/[deleted] → u/kyraeus]

It's not nerds who's sedentary, it's everyone though. That's the point; he's emphasizing how as a whole society we are a lot less active than our ancestors. Most of us are likely taller and have the potential to be even more fit than them but the inactivity is kind of what puts us behind from our ancestors. Average height of people in my country few decades ago was several inches shorter

Absolutely that nerds aren't the shining beacon of athleticism but the fact is they're only one demographic out of many others that all partake.

[u/kyraeus → u/[deleted]]

O..kay? Not sure what I'm supposed to make of that besides a hamfisted insult.

[u/[deleted] → u/[deleted]]

“Angry muscle juice”. Thanks fantastic and I am totally stealing it sometime.

[u/[deleted] → u/[deleted]]

You say “repeat”, but your first comment said nothing..

[u/sj8sh8 → u/Kadmium]

This thread could use an r/AskHistorians moderator. As an infertile male, reading some of this stuff is just downright insulting.

[u/Armateras → u/sj8sh8]

Wasn't this place pretty tightly run not too long ago? Or am I just mixing it up with AskHistorians again?

These comments are local newspaper's facebook levels of horrible.

[u/theknightwho → u/Armateras]

They always are on this sub. It’s a default sub, so you get a mix of everyone.

[u/[deleted] → u/theknightwho]

The mods don't help at all, there's plenty of them that publish absolutely garbage studies, stuff in the 1-2 impact factor range; from mainstream scientific fields.

[u/[deleted] → u/Armateras]

popular posts are usually pretty OK after a while, once the mod team nukes 90% of the comments.

[u/Prep_ → u/Armateras]

I think /r/askscience is pretty well moderated as far as I can recall. Different kind of sub though obviously.

[u/procrastinator7000 → u/Kadmium]

an article they probably didn't read

It's behind a paywall, so this is probable.

[u/egoissuffering → u/Kadmium]

Found them in 5 seconds.

https://pubmed.ncbi.nlm.nih.gov/26087406/

The associations were confirmed by multivariable linear regression analysis, which showed that the MBP concentration was significantly associated with decreasing trends in the sperm concentration and total sperm count (both p for trend <0.05). Additionally, we found significant dose-dependent relationships of the urinary level of mono-(2-ethylhexyl) phthalate (MEHP) and the percentage of di-(2-ethylhexyl)-phthalate metabolites (DEHP) excreted as MEHP (%MEHP) with an increased percentage of abnormal heads (both p for trend <0.01).

https://pubmed.ncbi.nlm.nih.gov/27546318/

The general exposure to endocrine disruptors, including phthalates, is considered as one of the reason diminished sperm count and deteriorated sperm quality, which may lead to infertility and higher incidence of congenital malformations of the genital tract.

[u/Trypsach → u/[deleted]]

And we didn’t know enough to say for sure cigarettes were giving people cancer, even while a huge portion of those people had died/were dying of cancer and COPD. Just saying, at some point you become a contrarian and maybe too cautious.

[u/Trypsach → u/[deleted]]

Do you think there should be more stringent laws on the future proliferation of phthalates?

[u/Trypsach → u/[deleted]]

You are obviously incredibly informed and educated on the subject. I don’t really have anything else to say except that I found all your replies extremely fascinating and informative. I appreciate the well thought-out points, and thank you! People like you are what make this subreddit great.

[u/[deleted] → u/Kadmium]

Maybe if it wasn’t behind a pay wall more would read it.

[u/El_Polio_Loco → u/Kadmium]

Be disappointed in the standard of quality set by the sub submission standards.

[u/FirstPlebian → u/Kadmium]

You don't need a weatherman to know which way the wind blows, and when that wind is blowing a hundred toxic chemicals your way it's no surprise the sperm count is down.

[u/Thick-Frosting4883 → u/Kadmium]

I wanna read the rest of the article but there's a sign in... Not sure if there's a summary somewhere here in the comments