What do you think of GMO's?

[Anomalocaris]

Can anti-GMO people produce scientifically rigorous studies that conclude that GMO foods are more harmful than beneficial?

Sure, depending on what fulcrum you want to lay harmful and beneficial upon. GMO isn't very good for biodiversity (based on projected economic effects if nothing else) - even though it requires biodiversity as a toolkit. But thats -on farm- biodiversity (albeit of a global sort), not exactly teeming with multitudinous expressions of the wonder of life as-is....eh?

Actually, modern agriculture is terrible for genetic and biodiversity. Most economically significant crops are genetically virtually identical across the globe. The ancestral wild plant often show more genetic diversity within several acres of their natural environment than their descendant crop plant show across all the farms in the whole world. See potatoes.

The question is would GMO make it significantly worse.