Yep, soy will cause problems. If you consume 1000g a day. I read through one of the studies where men lactated and stuff. And they took an ABSURD amount of soy. It didn't prove anything. If you made me eat that much corn, I think I would lactate.
Another one of the studies included a guy coming off of a cycle of steroids. And the test group was comprised of 12 individuals, I think. Anyway, once his data was removed from the test, there were negligible changes in testosterone. Testosterone actually increased, but it wasn't deemed significant.
You don't have anything to worry about with soy IMO. I know a lot of guys that take it because of cholesterol or allergen issues. Sorry I didn't dig up links to those studies, but I'm feeling lazy. I haven't seen anything that was conclusive and
relevant to the average person OR bodybuilder.
That's what you get for reading on T-Nation.