>>18283935well I appreciate the concern I guess
the answer is environmental estrogens
https://www.youtube.com/watch?v=OuE0WGtr8yAhavent actually watched that one, but I know his channel has a lot of content about this, so I pulled a random recent one up
diet
https://europepmc.org/article/MED/23934320https://pubmed.ncbi.nlm.nih.gov/12141930/there are a million diet related things you could put here, including obesity, so I picked a random one that is more obscure
men don't tend to eat as much real vitamin A anymore (liver, other organ meats, eggs/red meat to a much lesser extent)
instead people eat vitamin A precursors (beta carotene, other carotenoids) that actually have a bit of an estrogenizing effect on their own, on top of just not nearly being as potent as actual preformed vitamin A
the real difficult thing is that it probably takes multiple generations to see the effects of stuff like environmental estrogens and micronutrient inadequacies
this is an interesting example of this effect in cats. hard to really study multiple generations in humans in a controlled setting where you can isolate specific factors. the bad diet cats got progressively worse each generation, and it took more than one generation to fix it when they switched the bad diet lineage to the good diet
https://nourishingourchildren.org/2020/01/16/pottengers-cats/ 
