One candidate may be the chemical additives whose use greatly accelerated in the late 1960s.
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Phthalate esters have a diverse array of uses in consumer products, and they can be classified into 2 categories: low–molecular weight phthalates are frequently added to shampoos, cosmetics, lotions, and other personal care products to preserve scent,6 whereas high–molecular weight phthalates are used to produce vinyl plastics for diverse settings ranging from flooring, clear food wrap, and flexible plastic tubing commonly used in food manufaturing.85 Within the high–molecular weight category, di-2-ethylhexylphthalate (DEHP) is of particular interest because industrial processes to produce food frequently use plastic products containing DEHP.86 Racial and/or ethnic differences in phthalate exposures are well documented.87,88A robust literature, including numerous animal and human studies, shows that DEHP, benzyl butyl phthalate, and dibutyl phthalate are antiandrogenic and adversely affect male fetal genital development. These chemicals exert direct testicular toxicity, thereby reducing circulating testosterone concentrations within the body and increasing the risk of hypospadias and cryptorchidism at birth. These phthalates are also associated with changes in men’s hormone concentrations and changes in sperm motility and quantity.6,27–29,89–91 Mono-(2-ethylhexyl)phthalate, a DEHP metabolite, also interacts with 3 peroxisome proliferator–activated receptors,30 which play key roles in lipid and carbohydrate metabolism, providing biological plausibility for DEHP metabolites in contributing to childhood obesity and insulin resistance.92 Epidemiologic studies have also demonstrated an association between urinary phthalate metabolites and markers of oxidative stress.33,34 Laboratory studies have found that metabolites of phthalates are linked to oxidative stress.93,94 Oxidative stress appears to diminish the insulin-dependent stimulation of insulin-signaling elements and glucose transport activity95 and modify the endothelial relaxant nitric oxide, promoting vasoconstriction, platelet adhesion, and the release of proinflammatory cytokines, such as interleukin-1.96,97 Therefore, if phthalates are proinflammatory and increase oxidative stress, these effects could lead to changes to metabolic health outcomes. Emerging animal evidence also suggests that DEHP may produce arrhythmia,35 change metabolic profiles, and produce dysfunction in cardiac myocytes.36"
Chemical free, perfume free, shampoos, lotions and cosmetics are relatively easy to find. It's much harder to escape contact with plastics or metal cans. Milk, water, sodas, almost nothing comes in glass containers anymore.
I did find milk in glass bottles, and I found a water container which is made of glass. My drinking water is connected to a reverse osmosis filter, and that's the water I put in the bottle.
I use virtually no canned food. I even have gone back to buying dried beans and soaking them overnight before cooking them.
It sometimes seems like a losing battle, however. All meat comes plastic wrapped, for example. The only alternative would be to go back to the European way of buying meat, which is going every day to the butcher (or fishmonger) and cooking the meat or fish that day.
The drop in testosterone levels is not the only thing which has changed since the 1960s. There's also the incredible rise in obesity levels in a lot of countries. Other additives disrupt the endocrine system and cause obesity. No wonder I lose weight after a month or two in Italy living with my relatives.
All of this is explained here:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6298598/
I do think exposure to televisions, mobile phones, etc. may also play a role in all of this. There's been an alarming rise in primary brain tumors, for example.
