I can't cite any studies, I just don't like them. Plants talk to each other and to the rest of the environment in ways we haven't even started to understand, but we think it's cool we can modify their genetics in ways that nature would never allow, so they can resist crap tons of herbacides and still grow and allow for their neighbors to grow on top of them instead of needing space.
I can't cite a study, but i do see food sensitivities growing every year. The major culprits, wheat, soy and corn. Which 3 do you think are the most heavily GMO'd? coincidence? maybe, maybe not.
At the very least, if they are going to grow them and put them into the food supply, we should at least maintain the right to know what they are putting into the food supply. But without major lobbying dollars, we'll never have that right, because big farma, is exactly like big pharma. Money talks