This is a terribly designed study. Instead of isolating the possible source for the increased estradiol--as any credible scientific investigation would do--the conclusion of this study is muddled in vague possibilities: well, it could have been the soy-based protein which was responsible for the increased estradiol or it may have been one of the several plant derived substances-we just do not know which one!
Furthermore, there are too many plant-based substances in the supplements to know which if any is responsible for the increased estradiol. Clearly, the folks at J Int Soc Sports Nutr. should learn the scientific method and how to properly conduct a double-blind test which can focus on one specific substance.