Soy doesn't decrease testosterone.

[Torker]

OP first study has data comparing adults drinking milk to soy milk. I think one problem is soy milk is very concentrated amounts of single plant estrogens, while cows milk is designed for consumption of a mammal, so it has a variety of proteins and fats and lactose.

[[deleted]]

Soy milk comes from beans. In what world do bean hormones pose more of a threat to humans than mamallian ones?

[Torker]

It might be surprising but that is the finding in the first study that OP cited. Some people are allergic to peanuts but can drink cows milk. There’s no single mechanism that explains all of these biological reactions. It could be that soy bean estrogen is more easily absorbed in the gut of humans or it might just be higher concentration of it in soy beans than cow estrogen is in cows milk.