Soy isn't good for men, especially in higher quantaties, as it is
a) mostly GMO (thus not good for anyone)
b) a product that has large amounts of plant estrogens that disturb testosterone amounts in the body, amongst other things.
a) is correct, but you can deffinetly get certified non GMO soy.
b) is incorrect. That's completely false, phytoestrogens don't disturb in any way our testosterone levels. Even in large amounts. There's a guy in other internet forum that got tested before and after taking large amounts of soy derived products and even after years consuming these products his testosterone levels are normal.
So, if you keep distance from GMO Soy you don't need to worry =)
"extremely high levels of PEs have an unfavorable influence on hormone levels for both men and women, and may inhibit muscle gain and fat loss to some degree."
"A traditional daily intake of soy for someone may include 6 ounces of tofu, a half-cup or soy milk, and a ½ cup of edamame. That would provide roughly 75 mg of PEs. This is well below the amount necessary for having an unfavorable influence on hormone levels."
Still, that's only about 20g of protein. Not much to talk about, really. Albeit, it all helps, of course.