Here is a video and two articles on the health benefits of soy and the controversy surrounding it:

How Soy Isoflavones Protect Against Cancer (article)

&feature=player_embedded" target="_blank">Settling the Soy Controversy (video)

Huffington Post Article by Dr. Barnard

Soy is a phyto-estrogen, meaning “plant-estrogen”, just like flax, walnuts and other foods.  Phytoestrogens wrap around our healthy cells and protect them from excess hormones attaching to the cells.  Think of soy as a little 2-seat Cessna aircraft and regular estrogen as a jumbo jet.  When the Cessna is parked at the gate (or the estrogen receptor on our cells), the jumbo jet can not also park at that gate.  Excess hormones (like estrogen and testosterone) fuel hormone driven cancers such as breast, prostate, esophageal, ovarian, etc… Whole soy products have consistently shown to lower cancer rates and protect people from cancer.  They also lower cholesterol.  By whole soy products I mean tofu, tempeh, edamame and soymilk (only the kind made from whole soybeans, not soybean powder).  “Isolated soy proteins” are an extraction from the whole soybean and have not shown to have health benefitsl – these are the “soy” that you see in some veggie burgers and processed foods and baby formulas. However, they are used in place of meat, so that is a benefit – with meat comes cholesterol, fat and carcinogens, called heterocyclic amines, which initiate the cancer process.

Soy is the most genetically-modified food grown in the U.S.  So, for that reason, I prefer to use only organic soy as this is the best way to avoid GM soy.