Soy contains phytoestrogen in which fibroid tumors, breast and prostate cancer love to thrive on. There are forms of cancer which uses estrogen to give it energy for further development.
"Most modern soy foods are not fermented to neutralize toxins in soybeans, and are processed in a way that denatures proteins and increases levels of carcinogens."-FAQ section of "Myths and Truths about Soy Foods"
Personally I use rice or almond milk for my milk with cereal. Rice, coconut, and almond milk comes available sweeteend and unsweetened, and vanilla, chocolate, and plain flavors. I may use a little Tamari or soy souce in some foods. I generally avoid soy protein almost a 100%. I do use whey protein ar part of my diet for protein, sardine, wild salmon, fruits nots and grains(peanuts are not a true nut and I shy away from peanuts).
If you'd like to know more on the subject you can checkout this link below:
A study on such matter is also published from the Society of Endocrinology:
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