GMOs are such an interesting issue because it's simultaneously so personal (the food that you put in your mouth every day) and so difficult for most people without a science background to understand. I'm a PhD student in biology and I do a lot of genetics, but even I don't understand all of the nuances of modern genetic engineering, nor, especially, the potential shortcoming of various studies that aim to test the safety of these crops.
In my mind, there are really two separate issues at hand. 1) Are GMOs, in general, as a technique, safe? (Yes, definitely) 2) Are the specific genes that are being inserted into our food safe (Yes, but that is not necessarily so in general). I really have no problem with increased oversight to ensure that the latter point is true, but a vanishingly small portion of the anti-GMO crowd seem to even realize that there is a difference. I was living in California when there was a referendum to try to mandate that GMO foods get labeled as such, but the proposed labels would not have actually told you what the genetic modification is. The argument I kept hearing from the pro-labeling crowd was, "Don't you want to know what's in your food?" Well, first of all, I'm not exactly in a position to be able to intelligently second-guess the USDA or the FDA regarding food safety. But, more importantly, those labels would not tell you "what's in your food" any more than saying "we use some kind of pesticide or herbicide" would do so.