I recommend that you read The Whole Soy Story: the dark side of America's favorite health food by Kaayla T. Daniel, PhD. CCN. for the answer to your question.

I'm sure there are plenty of studies that show the health benefits of various subsidized grains and legumes. I wish pubmed listed all of those who funded them.

Soy is beneficial is you need an estrogen boost (like menopausal women). These studies probably used extracts or isolates. But overall Soy is not so great (beyond not so great)for digestion, thyroid ect..

Here are a couple of links:

http://civileats.com/2010/12/09/the-truth-about-soy-health-claims/

http://www.foodrenegade.com/dangers-of-soy/

Here is a great book to read that has a whole section on the dangers of soy...

The vegetarian myth by lierre keith

Interesting note: this author was attacked at a book reading by vegans. They threw hot pepper laden whip cream pies in her face. Wow, the power of meat is amazing.

Yah and although WAPF is not really Paleo per se, they have a lot of pretty informative articles on the dangers of soy. I'm not saying I agree with all of it, but I think I've read enough to know that soy carries far too many risks to consume it on purpose. If you are out with friends and have a couple of appetizer edamame beans, then fine whatever... but I avoid soy and soy based foods now.

I'm not sure the linked studies prove a protective effect from soy... didn't look at them all, but the few I checked were epidemiological. So, were there fewer cancers in the soy groups because of the soy consumption or because of some other factor soy eaters have in common?

Susan J. Komen for the Cure has a list of risk factors for breast cancer... soy is listed as "under study"... the explanation they provide is that some studies show a protective effect and others show a negative one. Individual links were not provided as far as I could tell though - just a long list of references that I do not have time to read through!

I am a breast cancer survivor and do not eat soy. My oncologist gave me the green light invoking the "Asians eat soy and have less breast cancer..." line. However, there is some controversy about the quantities/type of soy actually consumed in Asia. Also, soy seems to have many other negatives and few (if any) positives that I see no reason to take the risk.

BTW, I got breast cancer at 38 years old. No significant family history, brca negative. I was vegetarian from about age 19 until around 29 and ate lots of soy during this period. According to what I've read a cancerous tumor that can be felt has most likely been growing for about 8-10 years...

I would never take the risk & I was happily surprised that my girlfriend's Oncologist (she has breast cancer) told her to NEVER eat estrogen containing stuff (food) like soy ever in the future.