Critics of biotechnology say nature is incredibly complex and that GM technology is introducing a new genre of environmental and health questions. They argue that introducing foreign genes from distant species (e.g., a gene from a fish into a strawberry) increases the risk of allergenicity. Also, the risk of new toxins must be considered. And they point to lab research which has revealed possible unintended consequences of GMOs.

Jeremy Rifkin

When you introduce a genetically modified organism into the environment, it's not like introducing a chemical product, or even a nuclear product. Remember, [genetically modified] products are alive. So they're inherently more unpredictable in terms of what they'll do once they're out into the environment. Secondly, GMOs reproduce. Chemical products don't do that.

Third, they can mutate. Fourth, they can migrate and proliferate over wide regions. And fifth, you cannot easily recall them to the laboratory or clean them up. So when we're dealing with genetically modified organisms, we're dealing with a whole new genre of environmental and health questions, totally different than when we introduce chemical or even nuclear products into the environment. ...

Those very small bits [of DNA inserted into genetically modified organisms] can change in qualitative ways that GMO when it's introduced. Let's say you take a human growth hormone gene and place it into a salmon. That's just one gene. But if the salmon gets out into the marine ecosystem and it's growing twice as fast and twice as big, it can destabilize millions of years of relationships in the oceans. So one gene can be very, very powerful. ...

There's a second generation of genetically modified organisms being readied in R&D. These organisms are plants that act as chemical factories to produce genes that code for proteins to produce vaccines and chemicals and drugs and vitamins. ... This all sounds very good--except no one has stopped for even a moment and paused and asked this question: When we seed millions of acres of land with these plants, what happens to foraging birds, to insects, to microbes, to the other animals, when they come in contact and digest plants that are producing materials ranging from plastics to vaccines to pharmaceutical products? There hasn't been as much as a single congressional hearing, and as far as I know, there hasn't been a single parliamentary debate anywhere in the world, on introducing this second generation of pharmaceutical and chemical-producing plants.