I used to eat soy protein religiously.... soy burgers, soy chips, soy protein powder, tofu... you name it... and I have to say, I did notice a decrease in sexual function and libido after a while... so I'm not sure what science and medicine say, but from personal experience, there's something with soy to be concerned about if you're a guy... small amounts, I'm sure, are not a problem.. just don't overdo it... these days, alot of things contain soy protein, especially anything that's labeled as "carb-conscious" or dietetic... so I stay away from those types of foods