Several recent studies have shown the potential adverse health effects of glyphosate, the active ingredient in Roundup.  The latest study to do so was published in Food and Chemical Toxicology, and shows that even low concentrations of glyphosate possess estrogenic activity, which could induce breast cancer cell growth.  Glyphosate is commonly used for soybean cultivation, which is especially concerning because the researchers also found an additive estrogenic effect between glyphosate and phytoestrogens found in soybeans, which could amplify the herbicide’s effect on breast cancer cell growth.