The paper by Zhang et al.1 is a critical analysis of the results reported in the paper by Qaim and Zilbermann2 (Q&Z). In particular, Zhang et al. pointed out that it is untenable to project high yields for all GM crops in all developing countries on a single set of small trial data of Bt cotton from one season, under poor cropping management. More deficiencies in the data of Q&Z and much more in their interpretation have also been highlighted.