Feb 04 2014

The GMO Controversy

The controversy surrounding genetically modified organisms (GMO) has intrigued me for some time, and recently I have been reading everything I can on the topic. It is an excellent topic for skeptics – it is mainstream (not a fringe topic), it has real importance for society, there are complex scientific and logical issues to sort through, and the topic is rife with misinformation and motivated reasoning.

I wrote recently about the fact that beliefs concerning GMO tend to be dominated by two opposing narratives: GMO critics despise corporate control and greed, and fear the unnatural, while GMO advocates see this technology as an example of the triumph of human ingenuity and science. I admit that with regard to this issue my bias is toward the latter narrative, however, I can understand caution regarding huge corporations (the tobacco industry comes to mind).

But, as a skeptic I have really tried to follow a critical thinking process and pull back from my initial gut reactions. Here, then, is my overview of the issues regarding GMO.

A Brief History of GMO

GMO advocates are quick to point out that pretty much all the food consumed by humans have already been extensively modified by human activity. Corn, for example, was cultivated from teosinte, which looks nothing like modern corn. In fact, it took some detective work to figure out that they are essentially the same species.

Cultivation is mostly about artificial selection – saving the best plants from one year’s crop to provide the seeds for the following year. Repeat that a few thousand times, and you have the development of agriculture and all the food you recognize today.

Cultivation can also involve cross-pollination, creating a hybrid species in an attempt to get the best traits from closely related species. Using a combination of cross-pollination and artificial selection, breeders have created countless varieties of common plants. The black or purple tomato, for example, of which there are about 50 varieties, is high in flavanoids, which give them their color.  Orange carrots were developed by a fortuitous mutation resulting in high levels of beta-carotine. This turned carrots into an important staple crop as a source of vitamin A.

Breeders who are impatient to wait for a fortuitous mutation to occur developed what is called mutation breeding – exposing plants to chemicals or to radiation that increases the mutation rate. Between 1930 and 2007, 2540 mutagenic plant varietals have been released.

Genetic modification is the latest technique for changing organisms to suit our wants and needs. The technology involves various techniques for inserting one or more specific genes directly into a target organism. There are two basic types of GMO – transgenic and cisgenic. Cisgenic involves inserting genes from closely related species, ones that could potentially cross breed with the target species. Transgenic refers to inserting genes from distant species – even from different kingdoms of life, such as putting a gene from a bacterium into a plant.

There are four types of GM plants currently approved for use: herbicide tolerance, insecticide production, altered fatty acid composition (for canola oil), and virus resistance. Many other potential applications are in various stages of development.

GMO advocates are quick to point out that GM technology is nothing new, and that it is simply an extension of the various technologies we have used for thousands of years to alter organisms. This is overstating the case, however – transgenic GMO is not just a new technique, it also opens up new possibilities, like putting a gene from a bacterium into corn. But it is legitimate to put GMO in its proper historical context. It is not entirely new. Contamination of genes from other kingdoms even occurs in nature through horizontal gene transfer.

In any case, the “it’s not natural” argument is fallacious. Meanwhile, GMO should be looked upon as a powerful technology, and such technologies can have both powerfully good and powerfully bad consequences depending on how they are used.

Health Effects

There are various specific controversies surrounding GMOs. Perhaps the most emotionally-laden is that of potential health effects of GMO food. Critics have coined the term “frankenfood,” which is a politically useful slogan but not very useful as a concept. These concerns strike me mostly as the naturalistic fallacy. There is a legitimate concern, however, in that introducing new proteins into human food might lead to allergic reactions or unforeseen health consequences.

For this reason the safety of GMO food has been researched. The bottom line is that the research shows that existing GMOs are safe for human consumption and as animal feed.

A 2012 statement by the American Association for the Advancement of Science (AAAS) concluded: 

“As a result and contrary to popular misconceptions, GM crops are the most extensively tested crops ever added to our food supply. There are occasional claims that feeding GM foods to animals causes aberrations ranging from digestive disorders, to sterility, tumors and premature death. Although such claims are often sensationalized and receive a great deal of media attention, none have stood up to rigorous scientific scrutiny. Indeed, a recent review of a dozen well-designed long-term animal feeding studies comparing GM and non-GM potatoes, soy, rice, corn and triticale found that the GM and their non-GM counterparts are nutritionally equivalent.”

The National Academies of Science agrees: 

“To date, no adverse health effects attributed to genetic engineering have been documented in the human population.”

The World Health Organization also agrees: 

“GM foods currently traded on the international market have passed risk assessments in several countries and are not likely, nor have been shown, to present risks for human health.”

As referred to by the AAAS, reviews of animal feed studies have concluded: 

“Results obtained from testing GM food and feed in rodents indicate that large (at least 100-fold) ‘safety’ margins exist between animal exposure levels without observed adverse effects and estimated human daily intake. Results of feeding studies with feed derived from GM plants with improved agronomic properties, carried out in a wide range of livestock species, are discussed. The studies did not show any biologically relevant differences in the parameters tested between control and test animals.”

Critics claim there has not been enough testing. It is easy, however, to simply ask for more testing and make that seem as if it is the rational position. This is the same strategy used by antivaccinationists – no testing is ever enough, and the precautionary principle is endlessly invoked. Critics also have their studies to cherry pick, like the infamous Seralini study (now retracted).

It seems that we have as much of a consensus on the safety of current GMOs according to systematic reviews and expert panels as we do on the safety of vaccines, and perhaps even higher confidence intervals than the consensus that the planet is warming.

It can also be pointed out that plants that are produced through hybridization, which can chaotically mix in hundreds of genes, and plants resulting from mutagenic breeding do not require the same safety testing currently required of GMOs.

There is, for example, a GMO black tomato that takes two specific genes from the snapdragon and inserts them into a tomato to produce higher levels of flavanoids. This species must go through regulatory hoops, while the 50 varieties of black tomatoes made by cultivation, with much more unpredictable results, require no testing.

I do favor continued careful testing of GMO food for safety, but currently this is not a reason, in my opinion, to reject GMO, and the “frankenfood” label is unfair.

Environmental Effects

While the safety of GMO scientifically is rather straightforward, the net environmental impact of specific GMOs is a horrifically complex topic. This is a good time to recommend a series of articles by Nathaniel Johnson. He does a good job of exploring these issues and showing how complex they are. I don’t want this blog post to become a book, so I will only give a brief summary of the major issues.

Herbicide-tolerant plants, so-called “Roundup Ready” plants, are engineered to be resistant to the herbicide glyphosate. This allows farmers to control weeds by spraying their entire crop, even after the crop has sprouted. The advantages of herbicide-tolerant crops are that they are less labor intensive and they save money. They also reduce the use of soil tillage, which is bad for the soil and releases CO2 into the environment.

The disadvantage of herbicide tolerant crops is that they increase herbicide use, which gets into the environment, and which encourages the development of resistant weeds.

So what’s the net effect? That all depends on how these crops are used. Relying solely on glyphosate and glyphosate-resistant crops is turning out to be a bad idea, mainly due to the development of resistance among weeds. But, as one tool among many, it can be a net advantage. Farmers are better off using minimal, rather than no, tillage farming, and using a variety of herbicides, not just glyphosate.

The real issue (a theme that will keep cropping up – pun intended) is that the bottom line does not rest with GMO vs no-GMO, but how GMO crops are used as part of the overall farming practice.

This is also true of insecticide-producing GMOs, specifically Bt crops. Bt is an insecticide produced by a bacterium. In fact, it is a popular insecticide among organic farmers because it is environmentally safe. Bt GMOs have the gene from the bacterium inserted so they make their own Bt.

The advantages of Bt crops is that they are pest resistant and they reduce insecticide spraying. The disadvantage is that over-reliance on this one strategy results in pests becoming resistant to Bt. This is worsened by cross-pollination spreading the Bt trait to wild plants. There are also concerns about the effects of Bt on friendly insects (however, I would point out Bt is already used as a pesticide).

Again – the bottom line is that the Bt trait can be a useful addition to the farmer’s bag of tricks. But, they should mix Bt crops with non-Bt crops, to reduce the evolution of resistance, and use other insecticides.

This is a very quick overview of a complex topic, but I think it demonstrates the bottom line that GM crops with insect and herbicide resistance can be useful and even protect the environment, but they have to be used as part of an overall sustainable strategy.


The relationship between big agricultural companies, GMO, and farming is also a complex topic. I have found, however, that this is the most common source of criticism aimed at GMO and that most of the issues raised are actually myths. There are real issues, to be sure, and I will cover them, but first we have to dispense with the propaganda.

There are many big seed producing companies, the top three being Monsanto, DuPont, and Syngenta. For some reason Monsanto has become the poster boy for big agro corporate evil. The common claims made against Monsanto that you will find on the internet are largely not true. 

They do not sue farmers for seeds blowing into their fields. They have only pursued cases against farmers who deliberately tried to violate their contracts and essentially steal seed. Monsanto has not marketed a terminator seed that produces sterile seed. They obtained the rights of terminator seeds when they purchased another company, and then never brought them to market.

Monsanto is also not responsible for suicides among Indian farmers. In fact the suicide rate among farmers in India has gone down slightly since the introduction of GMO crops.

When we get past the hype and propaganda, what we find, in my opinion, is an industry that is behaving fairly typically (and actually there is much less to complain about than with many other industries, such as the pharmaceutical industry, cosmetic industry, oil industry, tobacco industry, etc.). This is where I feel the fair criticism lies – the big seed companies have overhyped their own products and encouraged overreliance on their GMOs as a single solution to farming’s complex issues. In this way they have been counterproductive.

They assured farmers, for example, that resistance to glyphosate would not occur, but of course it has. Seed companies have pursued a strategy of maximizing their market. They would be happy for farmers to heavily rely on their crops.

I am not defending this behavior, but let’s keep it in perspective. I start with the assumption that every single company in the world overhypes their products and services. In fact there is an entire profession (advertising) that exists solely for the purpose of hyping products and services. At the very least they put a maximally favorable spin on what they are selling.

Farmers, however, are not dumb. They don’t simply buy the corporate line whole. They are also doing what’s in their immediate best interest and not necessarily what is best for the planet long term. Government regulators also have their own take on agricultural issues.

I do think we need a push for evidence-based sustainable agriculture (it exists, but perhaps could be more institutionalized). For example, best practices might be more expensive or labor intensive for farmers and less profitable for the big seed companies, but there needs to be a standard in the industry and incentives for farmers to adhere to them.

One big issue is monoculture. The dilemma is that we are trying to squeeze an incredible amount of food energy out of limited land. We are pushing plants and the environment to their limits. Further, whenever you plant millions of something, something will evolve to eat it. It’s inevitable.

Monoculture, the reliance on a single cultivar, is counterproductive because it is inviting the inevitable blight or pest to destroy the entire crop. This happened to the Gros Michel banana monoculture, and is currently happening to the current Cavendish banana cultivar.

It can be argued that GMOs encourage monoculture, although to be clear the issue of monoculture predates and exists independent of GMO crops. For now farmers should be incentivised to mix in many varieties, even if they prefer the most profitable cultivars. They need to hedge their bets. Seed companies should be encouraged to not just make one variety with a favorable trait, but put that trait into many varieties.

In short we need to move as far away from monoculture as possible while maintaining the viability of agriculture as a business.

Another corporate issue that frequently is raised is that of patents themselves. Some GMO critics have a problem with the very notion of patents, saying they restrict innovation. Others argue that patents are necessary, otherwise no company could afford the huge investment that development requires. I have heard persuasive arguments on both sides, and honestly I don’t know what the bottom line is on this issue.

This probably means that a reasonable solution might be a compromise in the middle – tweaking patent laws to get the benefits but minimize any downsides.

For example, patents could come with a requirement to allow independent academic research. Another serious charge is that seed companies restrict independent research on their products, for fear that their property will be reverse engineered.

I wrote about this specific topic before, and will therefore just reference that article. The quick bottom line is that they do restrict research, but over the last decade have voluntarily allowed for independent academic research. The situation is therefore pretty good now, but can be improved.

Future Potential of GMO – Golden Rice and Beyond

This is a difficult issue to write about because when discussing the future there is a tendency to simply project one’s biases into the future. Having said that, I think there is good reason to be optimistic about the potential of GM as a technology.

Golden rice, for me, is a touchstone issue. I honestly cannot see any legitimate reason to oppose the use of golden rice, which is rice that has had genes for beta-carotene inserted. Since rice is a staple food in many parts of the world, and blindness and death from vitamin A deficiency in children is a huge problem. the introduction of golden rice seems like a no-brainer.

This technology is also ready for field testing, and therefore could be saving lives very soon. I get the sense that GMO critics oppose golden rice because such a home-run success for GMO would destroy their narrative (that it is all bad all the time).

GMwatch, for example argues that golden rice has not been adequately tested. However, they ignore a 2012 study (and their article has been updated that recently) showing that beta-carotene from golden rice is converted to Vitamin A in children at the same rate as pure beta-carotene from oil. They estimate that one bowl of rice would provide 60% of the daily vitamin A needed.

They and other critics argue that there are better solutions than this “high tech” fix, for example fortifying food, vitamin supplements, and growing carrots and other vegetables high in vitamin A.

However, such efforts are already underway, and while they have produced good results, are a long way from solving the problem of vitamin A deficiency. Golden rice is being advocated as an additional method (not instead of) these other methods.

In fact the issue has caused ex-Greenpeace president, Patrick Moore, to criticize his former organization for their opposition to golden rice.

There are many other potential applications of GM technology. Increasing the nutritional content of food is just one. Another is nitrogen fixation. Some plants use bacteria to fix their own nitrogen from the atmosphere. Others, including the cereals that make up most human calories, need to get their nitrogen from the soil, which means heavy fertilization. This has a huge environmental impact, a huge cost, and is one of the primary limiting factors in big agriculture.

Imagine if corn and wheat could fix their own nitrogen. This will probably never be developed with traditional breeding techniques – we need GM technology for this.

Another very promising goal is enhancing photosynthesis. Some plants have more efficient photosynthetic pathways than others. If we could get the optimal photosynthetic process into our major crops, that could increase yield significantly (estimates are by 20%).

Other potential applications include drought resistance, pathogen resistance, cold tolerance, and other ways of increasing yield.

One criticism of GM technology is that, while it may be good for applications that require 1-2 genes to accomplish, some traits (like drought resistance) involve many genes. Traditional breeding techniques might therefore be better for such complex traits.


GMOs are neither a panacea nor menace.  Genetic modification is simply a powerful technology, and its impact will depend entirely on how it is used. In fact, it is difficult to talk about GMOs as if they are one thing, and when someone does they are likely speaking from an ideological position. Rather, each individual GMO needs to be assessed on its own risks and merits.

Like many technologies, what matters most is how it is used. Safely feeding the growing population of the world in a sustainable way without having a major negative impact on the environment is a great challenge for our civilization. We should not accept uncritically the hype and spin of companies offering simple answers (that involve buying their product), but neither should we reject an entire technology based upon fear and misinformation.

In the end I think the conversation can be a healthy one – exploring all the complex issues of the use of GM technology can lead to better practices and solutions.

157 responses so far