The most ignored characteristic of soy is it's defense mechanism. To combat being eaten in the wild, it developed a hormone ability, that will stop the male, and female of any species from being able to procreate. This gives the plant a few rough years, until the barren herds nearby die, then nothing eats it anymore. Historically, healers in China knew this, but unfortunately for the people, the communist regime destroyed the literature, and killed the healers, then accepted American assurances that soy was a food, (possibly to control poplulation) making it a much consumed item in China.
Historical uses demanded it to be fermented to rid it of the hormone messing trait.