https://www.todaysdietitian.com/newarchives/040114p52.shtml"3. Soy causes feminization in men. High doses of phytoestrogens have been shown to impair male rats’ ability to produce offspring, but the same effect hasn’t been found in male humans.5 Since many of the concerns related to soy come from studies in rats and mice, it’s important to recognize that rodents metabolize soy isoflavones differently than humans, essentially making these studies inapplicable.2"
"While individual cases of sex hormone changes in men eating soyfoods have been reported, these men were consuming extremely high doses of soy (3 quarts of soymilk per day, in one case), and the effects were reversed when the soy intake was discontinued.6 A 2010 review in Fertility and Sterility concluded that “neither isoflavone supplements nor isoflavone-rich soy affect total or free testosterone levels” and that there’s “essentially no evidence from nine identified clinical studies that isoflavone exposure affects circulating estrogen levels in men.”7"
