The US–Mexico Dispute Over GM Corn Safety Could Transform American Agriculture

Mexico says genetically modified corn is a threat to its unique cultural diet and native strains of maize—and quite possibly the health of its citizens.

Illustration by The Epoch Times, Shutterstock, Freepik

Update: The United States won its legal dispute with Mexico. The United States-Mexico-Canada Agreement (USMCA) final ruling was reported on Dec. 20, 2024. Mexico has been ordered to comply with the findings and allow genetically modified corn to be imported.

Mexico’s effort to keep genetically modified corn out of the country is triggering a trade dispute with the United States and Canada that could affect the future of agriculture.

The trade dispute hinges on a key question: whether genetically modified (GM) corn poses a threat to human health.

U.S. trade representatives argue that it does not and wants to force GM corn into Mexico. Given that GM seed is used in 90 percent of U.S. crops, the dispute could have far-reaching effects should Mexico win. Beyond the U.S. agricultural sector, it could damage the German and Chinese companies that make and sell those seeds.

Bayer, the company that bought seed giant Monsanto, and Chinese state-owned Syngenta didn’t respond to requests for comment by press time.

A Battle Over Biotechnology

Corn has fed previous trade battles between Mexico and the United States, with Mexican producers previously protesting the North American Free Trade Agreement for allowing U.S. corn in without restriction. In the latest chapter, Mexico issued a presidential decree in February 2023 that bans GM corn in tortillas and dough and signaled the country’s intention to gradually replace GM corn in all animal and human foods.

Mexicans participate in a march of hundreds of corn producers protesting against the North American Free Trade Agreement and resulting maize imports from the United States, in Mexico City on Jan. 31, 2008. Corn has been a point of contention between Mexico and the United States. LUIS ACOSTA/AFP via Getty Images

Canada—which is deeply integrated into U.S. and Mexican agricultural trade—and the United States both opposed the ban.

Mexico has kept genetically modified corn from being grown within its borders for 25 years in an effort to protect both its citizens’ health and ancient strains of maize. Corn is a staple crop eaten in 89 percent of Mexican meals.

The United States has largely disregarded health concerns arising from GM crops and has spent the past year working to prove Mexico’s 2023 decree violates the United States–Mexico–Canada Agreement (USMCA).

The restrictions, originally slated to go into effect this year, set off a disagreement now in the hands of a USMCA trade panel after Mexico and the United States failed to resolve it through negotiations.

The United States contends that there’s no scientific evidence that GM corn is unsafe to eat, a claim that Mexico refutes. Mexico says the United States hasn’t presented any evidence of GM corn’s long-term safety, particularly when eaten at high levels.

Corn consumption is 10 times higher in Mexico, raising concerns among its medical and governmental leaders about research linking GM crops to health issues.

Clashing Visions and the Future of Agriculture

The trade disagreement highlights clashing ideological values and interests. Mexico has concerns for public health and indigenous maize. The United States aims to protect U.S. farmers, food security, and the future of agricultural biotechnology.

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Lucy Sharratt, coordinator of the Canadian Biotechnology Action Network Lucy Sharratt

Ultimately, the three-member USMCA panel has to sort through the arguments, science, and finer points of indigenous legal rights to make a decision. Lucy Sharratt, coordinator of the Canadian Biotechnology Action Network, said the ruling could generate cultural and environmental shockwaves.

“If the panel pays attention to the science, they should come to the same conclusion as the Mexican government. If they’re swayed by politics and the power behind the technology, it’s going to be difficult for them to see the reality of the science,” she told The Epoch Times. “This is a hugely significant decision the panel has before them.”

The Canadian Biotechnology Action Network, a group that raises awareness about the genetic engineering of food, was originally invited to share its opinion with the trade tribunal, but the offer was rescinded at the request of the U.S. and Canadian governments.

Mexico’s Case

Mexico filed a 200-page response to the U.S. trade violation complaint, which many observers say fulfilled the onus of its argument. It offered 66 articles in peer-reviewed journals pointing to GM corn’s associated health risks including increased damage to organs, cancer, antibiotic resistance, and reduced nutritional content.

Mexico’s decree also included a ban on glyphosate originally intended to go into effect on April 1, but the government pushed back that date while researching alternatives available in suitable quantities.

GM corn is tightly wed to glyphosate, the key ingredient in RoundUp and other herbicides. That’s because one of the most prominent traits in GM corn is resistance to glyphosate, the main ingredient in RoundUp. Monsanto, the German firm making most of the GM corn grown in the United States, calls the corn “Roundup Ready.” A rise in the use of glyphosate closely paralleled the rise in use of GM corn seed.

The amount of glyphosate used has increased in tandem with the increased use of genetically modified soy and corn. The Epoch Times

Additionally, Mexico’s report included 74 studies and papers on the risks of glyphosate, pointing to research documenting residues found on GM corn and concerns that the volume of corn that Mexicans eat creates the need for a different safety standard. Mexico’s decree isn’t an outright trade ban, but it does create the need for suitable replacements for both GM corn and glyphosate.

Although its language is vague, the decree calls for agricultural groups to offer input to Mexican agencies on how to design, promote, and implement alternatives to glyphosate.

The Glyphosate Issue

Glyphosate has become an important topic of research, and studies now suggest that it has several potential consequences on human physiology.

A 2014 study published in the Journal of Organic Systems looked at two decades of information on the rising rates of chronic diseases and their association with glyphosate use. Correlation doesn’t prove causation, but graph after graph of epidemiological data of 22 diseases reveal sharp increases that coincide with the accelerating use of glyphosate.

The study found highly significant correlations between glyphosate applications and hypertension, stroke, diabetes prevalence and incidence, obesity, Alzheimer’s disease, autism, multiple sclerosis, inflammatory bowel disease, several types of cancer, intestinal infections, and more. Researchers used the Pearson correlation coefficient, the most common way to measure correlation.

Additionally, Roundup Ready corn and soy in the United States were also found to have highly significant correlations with many of the same diseases. The authors concluded that the results warrant additional research on these relationships.

Research done in Mexico has found glyphosate in the urine of children and adults, as well as evidence of it in industrial and native foods.

Roundup (glyphosate) is typically sprayed on fields prior to production to kill any weeds. With Roundup Ready seed varieties, the herbicide can be applied to young crops to knock down competing weeds. JEAN-FRANCOIS MONIER/AFP via Getty Images

Several diseases have increased in close parallel to the rising use of glyphosate and GE crops. The Epoch Times

Unsatisfied With the Science

Mexico has objected to some of the research that the United States was citing during negotiations, including sources that were not peer-reviewed, were more than a decade old, or were funded by biotech companies. Mexico also raised concerns about the lack of long-term studies on humans eating GM corn, according to Timothy A. Wise, senior adviser for the Institute of Agriculture and Trade Policy.

Timothy A. Wise, senior adviser, Institute of Agriculture and Trade Policy

“Nobody’s done those studies, and the U.S. government knows they don’t exist,” he told The Epoch Times. “And they don’t want them to exist, because the only thing that would happen if they do exist is [to] upset the biotech industry.”

The American Farm Bureau Federation said the dispute touches lives on both sides of the border, denying “families in Mexico safe and affordable food.”

The United States turned down a proposal to do a joint study with Mexico on the health impacts of GM corn in early attempts to settle the trade disagreement.

Fernando Bejarano, executive director of Pesticide Action Network in Mexico, told The Epoch Times that the United States’ rejection of this proposal gives Mexico reason to doubt that the United States will acknowledge the potential risks posed by glyphosate and GM corn.

Mexico has rightly decided that it’s better to prevent problems with glyphosate than it is to take irresponsible risks, he said. It’s the opposite tactic of the United States’, which relies on proof of harm after the fact.

A street vendor weighs traditional corn tortillas in Mexico City on June 18, 2008. Corn's prevalence in Mexican meals raises the country's rates of exposure to genetically modified corn and glyphosate. Ronaldo Schemidt/AFP via Getty Images

The United States had until March 26 to file its rebuttal with the trade tribunal. The Mexican section of the secretariat for the USMCA told The Epoch Times on April 2 that it had not received the United States’ rebuttal, and that the “parties are in the process of revising the timeline,” which will be published when the new schedule is approved. A final decision in the dispute is expected by November.

Several non-governmental organizations were asked to present their perspectives to the trade panel. Some were accepted and have begun making those documents public.

One of those is the Center for Food Safety (CFS), a nonprofit public interest and environmental advocacy organization aimed at protecting human health. The group has raised issues with the trustworthiness of the U.S. regulatory system.

The CFS said Mexico shouldn’t be expected to rely on the claims offered by the United States that GM corn is safe because there is no oversight in the “sham” U.S. regulatory system, which is filled with “loopholes” and “inconsistencies.” The group shared its report online on March 24.

The CFS points to the U.S. Food and Drug Administration’s plant biotechnology consultation program, which puts the onus of safety on the backs of the corporations manufacturing the food.

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“When governmental review is optional; and even when it’s conducted, starts and ends with the regulated company’s safety assurances—what’s the point?” Bill Freese, a biotech regulation expert and science director for the CFS, asked in a news release. “The aim is to quell concerns and promote acceptance of GMOs, domestically and abroad, rather than critically evaluate potential toxicity or allergenicity.”

Battle Over Science

Thus far, the United States has stood by its argument that GM safety has been proven, and those who support the actions of the Office of the U.S. Trade Representative (USTR) criticize Mexico for not practicing sound science.

“We must continue using every available option to stop this unscientific and economically damaging ban on genetically modified corn from coming into effect,” Sen. Deb Fischer (R-Neb.), a member of the Senate Agriculture Committee, said in a statement. “As I have said before, there can be zero compromise with Mexico on this issue.”

Sen. Chuck Grassley (R-Iowa) tweeted that Mexico’s ban is unscientific and that if the experts need proof that GM corn is safe, they can look at him as a case study because he has eaten GMOs for 30 years. The post was shared on the Office of the USTR’s website.

Lin Warfel, farmer Lin Warfel

Lin Warfel, an 83-year-old farmer from Illinois, told The Epoch Times that he has used glyphosate on his crops since it came to market in 1996 and is perfectly healthy—as are many of his peers. He suspects that lawsuits over illnesses linked to the chemical have to do with the mishandling of it.

“The GM corn is safe. It doesn’t make any difference if you eat 1 pound or 10 pounds,” he said.

Mr. Warfel described GM seed as a blessing that has allowed him to increase yields, feed more people, and decrease his chemical applications.

Genetic modification involves inserting genes from organisms with desirable traits—such as being resistant to insects, drought, or herbicides—into seeds to produce those traits. For instance, a soil bacterium called Bacillus thuringienus (Bt) is a commonly engineered trait, as it produces a natural insecticide.

According to the Food and Drug Administration, the idea is that less chemical application is needed on GM corn, which Mr. Warfel claims has held true on his farm.

While some seed modifications aim to reduce herbicide use, others enable plants to withstand even greater herbicide exposures. maRRitch/Shutterstock

Toxic Residues Are Increasing

While the science surrounding GM corn is debated, and the influence it has on farming practice is varied, some experts say that should not change whether Mexico can prohibit potentially harmful substances from entering its country.

“Every country has a sovereign right to determine what technology, what GMOs [genetically modified organisms] are going to be allowed in their country,” Chuck Benbrook, an expert consultant in genetically engineered food and food safety, told The Epoch Times. “The U.S. government has been very aggressive in trying to push this technology on countries around the world.”

Despite the new varieties of GM corn, observers say toxic load to farms has increased since GM seeds were introduced to the market. There are many unknowns about the technology, Mr. Benbrook said.

Chuck Benbrook, consultant, genetically engineered food and food safety Chuck Benbrook

For one, technology is evolving under the umbrella of original approval without updated safety testing, he said. More traits are being developed as older ones are found to no longer work. Additionally, the levels of safety were based on much lower toxin exposure than what Americans are currently exposed to.

Mr. Benbrook said he is is hopeful that the dispute will force the U.S. government and biotech and food companies to conduct more thorough research. The GM issue as a whole hasn’t received much attention in the past 15 years, he said.

Mr. Benbrook helped write a report for Friends of the Earth—one of eight non-governmental organizations invited to submit comments to the trade panel.

The report concludes that the United States is essentially asking Mexico to trust the safety assessments conducted as many as 30 years ago.

“The Mexican government is both wise and on solid ground in refusing to allow its people to participate in the experiment that the U.S. government is seeking to impose on Mexico,” the report states.

The report also notes that there has been a roughly four-fold increase in pesticides and toxins in corn production since the early 1990s. The total number of pesticides and pesticidal compounds used per acre in the United States was 2.6 in 1990 and grew to 13.4 in 2023, illustrating a rising reliance—and human exposure—to toxins.

“There’s no science the U.S. government can point to that even suggests that higher levels of exposure to multiple toxins, as opposed to just one or two, isn’t posing significantly higher risks,” Mr. Benbrook said. “They assume that’s the case. They hope that’s the case, but they don’t have the science to back it up.”

Glyphosate’s Dangers

A growing concern about glyphosate comes from studies suggesting that it disrupts hormones. The Endocrine Society co-authored a report in February categorizing glyphosate among the top four most threatening endocrine-disrupting chemicals—meaning that it has a toxic effect on hormones—which play a role in many bodily functions and processes. Glyphosate has eight of 10 characteristics of an endocrine-disrupting chemical, according to the report.

The International Agency for Research on Cancer (IARC) classified glyphosate as “probably carcinogenic to humans” in 2015—based on “limited” evidence of cancer in humans and “sufficient” evidence in animal studies. The agency also found strong evidence for genotoxicity.

Lynne Finnerty, senior director of public affairs at the Biotechnology Innovation Organization (BIO), told The Epoch Times in an email that the IARC report has been called into question and that other organizations have declared that foods with crops that were treated with glyphosate are safe. Those organizations include the U.S. Environmental Protection Agency and the European Food Safety Agency.

“There are already thousands of studies that have contributed to a global consensus, and findings by government bodies around the world, that biotech foods are safe to consume,” Ms. Finnerty said. “How many more studies are needed? Mexico is searching for a problem that simply does not exist.”

Ms. Finnerty noted that Mexico’s secondary argument about GM imports threatening its native corn doesn’t hold weight because GM seed is not sold in Mexico. There’s no threat that imports could pose a risk of cross-hybridization with their native corn crops, she said.

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The BIO contends that Mexico is simply making political decisions. The decree, the group said in a news release, was not preceded by a formal change in safety or regulatory policy but only an administration change. In fact, nothing about GM science had changed, the BIO stated.

“Science-based, predictable regulation of trade in food and feed products is critical to ensuring the flow of trade that meets the world’s food needs,” Nancy Travis, the BIO’s vice president for international affairs, said.

The U.S. government’s response to Mexico’s decree also appears to be entirely political, according to Mr. Wise.

“The biotech industry and the farmers who are on board with biotech in the U.S. are screaming at the U.S. government to stop Mexico from putting restrictions on GM crops for anything, no matter how small the market, no matter how small the impact. I think the U.S. is completely on board with the biotech industry in this case,” he said.

Effect on US Farming

So far, Mexico hasn’t enforced its ban as it relates to imports, but if it did, Mr. Warfel said it could have an impact on the price that he can get in the market for corn and whether his farm breaks even or makes a profit.

Mexico’s proposed policy would cost more than 30,000 U.S. jobs, and the cost of corn in Mexico would rise by 19 percent in the next 10 years, according to a September 2022 report drafted by World Perspectives.

Farmers harvest corn near McIntire, Iowa, on Oct. 31, 2023. A ban on genetically modified corn could send shockwaves through the U.S. agriculture industry. Photo by Scott Olson/Getty Images

Farm industry groups here praised the USTR for pursuing the dispute with USMCA.

“U.S. officials have exhausted every avenue trying to resolve this conflict and are left with no other choice but to turn to a third-party panel in hopes of quickly rectifying this issue. We are deeply appreciative of USTR for standing up for America’s corn growers,” the National Corn Growers Association said in a statement.

Are There Only 2 Options?

Others observe that the United States hasn’t acted in good faith to resolve the matter, however.

Ms. Sharratt said it wouldn’t be that complicated for the United States to work with Mexico by adapting the type of white corn that it grows and exports to the country to be free of genetic engineering—allowing a compromise that might benefit both countries.

Corn grown on communal land in a San Miguel Xicalco neighborhood in Mexico City on Oct. 4, 2022. Mexico grows many varieties of indigenous maize. ALFREDO ESTRELLA/AFP via Getty Images

“Forcing GMO corn into Mexico is a political move. It’s not a move necessary for U.S. farmers. There are strong alternatives,” she said.

Mr. Bejarano noted that Mexico’s decree would actually benefit those farmers already growing organic, non-GMO white corn in the United States.

“It’s the right of Mexico to decide what kind of protection is needed,” he said. “We can have free trade without sacrificing the constitutional duties of the government to protect their own people.”

Should Mexico win the trade dispute, it’s unlikely that U.S. consumers would not take note. Such a weighty ruling would also likely trigger closer scrutiny of the science regarding GM corn and other modified food crops. In the end, Mexico could become a harbinger for the decline of U.S. dependence on foreign seed companies and the herbicides that pair so well with their genetically modified offerings.