The public debate about genetically modified organisms (GMOs) seems to have quieted down a bit, but I suspect that is an artifact of the pandemic (all news is COVID news these days). Still, public concern about the health effects and overall safety of GMOs remains high, and is the single issue in which there is the greatest disconnect between public opinion and scientific consensus.

In a 2020 Pew Research survey 38% of Americans felt GMOs were unsafe, 27% felt they were safe, and 33% did not know. These numbers varied significantly by country, with the mean being 48/13/37 respectively. Australia was the only country to reach parity, with 31% saying they are safe and 31% unsafe, and no country had a plurality of the public believing GMOs are safe.

Meanwhile, there is a strong scientific consensus that GMO crops are indeed safe for human or animal consumption. According to a 2016 study by the National Academies of Sciences, Engineering and Medicine:

while recognizing the inherent difficulty of detecting subtle or long-term effects on health or the environment, the study committee found no substantiated evidence of a difference in risks to human health between current commercially available genetically engineered (GE) crops and conventionally bred crops, nor did it find conclusive cause-and-effect evidence of environmental problems from the GE crops.

Specifically regarding human health:

The committee carefully searched all available research studies for persuasive evidence of adverse health effects directly attributable to consumption of foods derived from GE crops but found none.

Those who wish to fearmonger about GMOs (as they do about vaccines, cell phones, or other alleged hazards) can always demand more evidence, or claim risks that have eluded existing evidence. This is always possible because it is impossible to prove zero risk for anything. And of course we legitimately need to be on the look out for evidence of subtle harm missed by prior research. But at some point the evidence showing a lack of risk is robust enough that we can be relatively confident any remaining possible risk is small enough to safely ignore.

We can also follow basic scientific principles there is no scientific reason to suspect that GMOs should be unsafe for consumption. There is no plausible mechanism, and public fears are mostly based on gross misunderstandings of the basic science, such as the false notions that only GMOs have DNA or that they can alter the genes of those who consume them. Often fears are based upon an overapplication of the precautionary principle, while ignoring a more proper risk vs benefit analysis, and further ignoring comparisons to the alternatives. It is reasonable to argue that not using genetic technology to improve agriculture is a greater risk than using it. Further, techniques for developing new cultivars that are not categorized as genetic modification may pose a higher risk of introducing harmful substances into the food chain.

There is also the point that GMO is a somewhat arbitrary category, targeting certain technologies but not others, based, it appears, on nothing but a vague ick factor. For example, mutation farming, in which radiation or chemicals are used to increase the rate of mutation in the hopes that a rare mutation will prove useful, is not considered GMO. Another example is forced hybridization, in which species that would not normally cross fertilize are forced to do so. There is also greater fear for transgenic GMOs (where a gene is inserted from a distant species) vs cisgenic (where the inserted gene is from a closely related species). Again, there is no scientific basis for this distinction, only an ick factors that derives from the idea that a fish gene is being inserted into a tomato. Such distinctions are not genetically important, however (apart from some technical aspects that dont affect the final product), as evidenced by the fact that humans and bananas share about 60% of their genes. In short there is no such thing as a fish gene.

The lines between different techniques for developing crops is getting further blurred over time, making the GMO category increasingly arbitrary and scientifically dubious. But this can have a good effect from a regulatory perspective, in that it can allow certain techniques to escape from the unnecessarily harsh regulatory environment imposed on GMOs. One such emerging category is gene-edited.

Gene-edited crops are those that are created by altering existing genes already present within the genome, rather than inserting an entirely new gene. This is an increasingly important category because of innovations like CRISPR, that makes gene editing relatively quick, cheap, and easy. In fact gene editing is becoming so powerful it may, to some extent, render the GMO category obsolete.

The political fight over how to regulate gene-edited crops is now underway. There has been partial success in some countries and regulatory zones, and failures in others. The landscape is complex, however. In the US, for example, regulating crops falls under the FDA, EPA, and USDA, and these agencies can have conflicting categories and regulations. Currently:

The three agencies regulate the characteristics of the products themselves and not the process to develop it. Gene edited crops lacking foreign genes (which trigger regulation as GMOs) and that do not pose a risk to other plants, and gene-edited food showing no food safety attributes different from those of traditionally bred crops, are not subject to pre-market regulatory evaluation. It remains the responsibility of the developer to assure that products placed on the market are safe for use and consumption.

Currently the EU and New Zealand are the only legislatures that regulate gene edited crops as if they were GMOs. Just recently the UK moved to relax regulations on gene edited crops, essentially allowing their development and use in the UK (thanks to Brexit). Canada, Japan, Brazil, Argentina, Colombia, Chile, Paraguay, and Uruguay also have relaxed regulations for gene edited crops. The rest of the world has not made a determination.

This is an important public debate to have. This is especially true because anti-GMO attitudes are one of the few topics where the knowledge deficit model of science communication is actually effective. In other words people who are anti-GMO are largely open to changing their minds if they are given more scientifically accurate information, because being anti-GMO is largely based on misinformation (rather than something harder to change like tribal affiliation or ideology). The stakes here are also very high. The experience of golden rice is a good example this is a GMO that can potentially save millions of poor children from blindness or death, and its deployment is being slowed by unscientific opposition and unreasonably burdensome regulations.

The fight for gene edited crops may be politically easier to win, and increasingly more important as technology shifts in this direction anyway.

Founder and currently Executive Editor of Science-Based Medicine Steven Novella, MD is an academic clinical neurologist at the Yale University School of Medicine. He is also the host and producer of the popular weekly science podcast, The Skeptics Guide to the Universe, and the author of the NeuroLogicaBlog, a daily blog that covers news and issues in neuroscience, but also general science, scientific skepticism, philosophy of science, critical thinking, and the intersection of science with the media and society. Dr. Novella also has produced two courses with The Great Courses, and published a book on critical thinking - also called The Skeptics Guide to the Universe.

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Gene Edited vs Genetically Modified | Science-Based Medicine