It all depends, doesn't it? We even see lots of issues in horses that consume soy products. Could it be because it is Genetically-Modified-Organisms soy? Maybe, but I also know of 2 horses (one male one female)that are chronically laminitic (hoof inflammation) on an organic soy feed product and I know for certain that one of them improved each time the product was removed from the diet! The other owner never tried.
Fermented soy is also generally much safer to consume that straight and soy is high in phytoesytrogens that can interfere with one's own hormones.....
Personally, with my thyroid condition and soy interfering with it too, I'd rather stay away from soy!