I'd like to see citations for this section. Without citations it's difficult to interpret this statement as anything more than speculation. They are referring to a retracted (and republished, however not without harsh criticism by most scientists in the field, see [https://www.geneticliteracyproject.org/2014/06/24/scientists-react-to-republished-seralini-maize-rat-study/] for comments by scientists) paper by Seralini et al. To me, the "few studies" that hint at those effects amount to just this single, controversial and scientifically questionable study. Then again we don't know for sure how many studies they are referring to because none were cited.