There are two different kinds of estrogen receptors. Up to a certain amount of soy it affects mainly the receptors not associated with harmful effects. So a certain amount of soy per day is safe & healthy. But beyond that it can be problematic.

https://nutritionfacts.org/video/how-much-soy-is-too-much/

It should be noted that feeding babies milk from cows is an "experiment" too and there's a lot of evidence it's not good for them.

Asians who eat much soy probably have evolved a different response to it than other populations. Similar to how northern Europeans evolved better lactose digestion than the rest of the world.

Probably? On what basis?

This is addressed explicitly in the article:

> Cultures with a long-time reliance on soy protein apparently realized this early, Patisaul adds. For instance, the compounds in soy are known to interfere with the body’s uptake of iodine, an element necessary for healthy functioning of the hormones produced by the thyroid gland. Chinese farmers first cultivated soybeans about 1100 B.C., so it’s not surprising, she notes, that many Asian diets gradually evolved to contain foods that contain extra high levels of iodine, such as seaweeds.

Many of the forms of soy eaten in Asia are fermented or otherwise chemically changed to the point that their negative effects could be less pronounced. Soy sauce, miso and natto are some of many examples.

Something to note is that 93 percent of soy grown in the United States is genetically modified [0].

[0]: https://www.ers.usda.gov/data-products/adoption-of-genetical...

Also worth noting what kind of GE we're talking about: https://en.wikipedia.org/wiki/Genetically_modified_soybean

tl;dr: mostly pesticide resistance.

That has significant environmental/economic consequences, but those edits (probably) don't change how soy interacts with endocrine receptors.

Ive only heard of herbicide resistance, aka roundup ready. The bt modification (Cry1Ac protein from Bacillus thuringiensis), afaik, is itself a pesticide, or produces pesticide.

Edit: I suppose "pest" could refer to weeds and insects? I may have been thinking insecticide.

>That has significant environmental/economic consequences, but those edits (probably) don't change how soy interacts with endocrine receptors.

Pesticide resistant crops being completely doused in glyphosate right before harvest probably does have an impact on health though.

http://people.csail.mit.edu/seneff/ITX_2013_06_04_Seneff.pdf

Absolutely, but that's not isolated to soybeans. Plus we've been abusing toxic pesticides for decades - that's just greedy human shortsightedness.

I don't know how different the number is for the US specifically but around 85% of soy grown is used for animal feed. I don't know what the intersection of GMO and animal feed is, but anecdotally, a lot of the soy I see for human consumption is non-gmo.

But that raises the question of what soy's GMO status has to do with its affect on the endocrine system?

Is there any evidence to suggest that genetically-modified soy has higher or lower phytoestrogen content as compared with non-GMO soy?

Soy (and other crops) are modified to be resistant to pesticides and pests, so I presume it makes no difference for their phytoestrogen contents. For example, glyphosate ("Roundup") resistant crops are only modified to have a different version (which still preforms the same function) of the enzyme that would otherwise have been inhibited by glyphosate, IIRC.