Can we please lay this one to rest already? Soy has been villainized enough. Let's address the two major concerns with soy.
Soy is all GMO --
No. Between 90-95% of soy (which is mostly GMO) is sold for livestock feed, not direct human consumption. So if you're worried about consuming GMO soy, stop eating meat from factory farms and/or anything that is 'convenience' or 'fast food.'
In reality, most of the soy targeted to vegans and vegetarians is clearly labelled as non-GMO and/or organic. Most grocery stores these days carry non-GMO soy milk, faux meats, ice cream, etc.
Soy messes with your hormones and/or will give you man boobs --
Again, no. The topic of debate here is the presence of phytoestrogens in soy. And yes, they're in there. But here's the thing, they're in a lot of things; generally highest in nuts and seeds. Guess what? Flaxseeds have nearly triple the amount present in soy. Yet nobody has concern about taking flaxseed supplements, adding it to smoothies, or even drinking the latest flax milk on the market.
Secondly, the studies done on soy in relation to hormones have been pretty limited so far, and those pointing to ill effects studied consumption of soy far higher than the average person would ever consume. But in the real world, we know that populations that consume more soy don't have lower birth rates (which would indicate fertility issues) or more men suffering from man boobs. In fact, men consuming soy have had health benefits, such as lower risk of prostate cancer and better chances of survival after diagnosis.
Lastly, and here's probably the most important point... It makes no sense whatsoever to say, "I stick with cow's milk. Soy milk can mess up your hormones." Do people not realize that dairy contains real estrogen? Phytoestrogens have a very weak effect in the body. Real estrogen (and all the other hormones present in dairy), on the other hand, are far more impactful. Fun fact: 60-80% of the estrogen the populace consumes comes from dairy. That's far more concerning to your health and hormonal balance than the small amount of phytoestrogens you'll consume from a glass of soy milk and a serving of edamame.
And if you're looking for guidelines, here goes. The overwhelming majority of the science indicates that soy is fine. One or two servings a day is perfectly healthy. Make it mostly whole and/or fermented soy goods (as opposed to isolates and fillers in processed foods). Bonus: Soy products have been shown to lower serum cholesterol levels. Now, go tell your anti-soy/pro-dairy friends.
Sources for more information:
Livestrong: Foods That Contain Phytoestrogen
Harvard Gazette: Hormones in Milk Can Be Dangerous
PCRM: Ask the Expert - Soy