Not to open yet another can of worms, BUT do asians eat soy in any form or just fermented soy for the most part?
Other than edamame most of the soy is fermented such as tofu and soy sauce. This is not the only phytoestrogen source they consume though. They also consume a lot of seaweed, also phytoestrogen rich. The fruits and vegetables they eat will also provide phytoestrogens, and flavonoids that also provide phytoestrogen-like effects.