Soy phytoestrogens are basically a myth. Soy isoflavones are structurally similar to estrogen, so it was a reasonable hypothesis that they would behave like es

Soy phytoestrogens are basically a myth. Soy isoflavones are structurally similar to estrogen, so it was a reasonable hypothesis that they would behave like estrogen in the human body. But this has mostly not been born out by evidence. In particular, it is now clear that soy isoflavones have no measurable impact on male sex hormones. Isoflavones do have some impact on estrogen receptors (the correct term for this is "selective estrogen receptor modulator"), and indeed this causes some health benefits. But in healthy humans, there is very little reason to think they cause any negative effects. I think most of the fear mongering about this has come from body builders, who worry that soy will lower their testosterone and sabotage their efforts. This we now know it does not do.