Mexico’s lower house of Congress approved a constitutional reform sponsored by President Claudia Sheinbaum to ban the planting of genetically modified (GM) corn this week.

The reform won passage on a 409 to 69 vote and must be approved by the Senate before it can be sent to Sheinbaum for her signature.

Coming just two months after a trade dispute panel ruled that Mexico’s restrictions on GM corn violate the U.S.-Mexico-Canada Agreement (USMCA), final passage of the bill could produce more tension with the United States, according to the news agency Reuters.

Only three weeks ago, the U.S. Department of Agriculture celebrated Mexico’s acceptance of the ruling while conceding that it would continue to monitor Mexico’s compliance.

As this reform advances, the relationship with the United States — from whom Mexico buys about US $5 billion of GM corn each year, mostly for livestock feed — will face “uncertainty,” the Agricultural Markets Consulting Group (GCMA), a major consultancy in Mexico, believes.

“Following the adverse ruling by the USMCA dispute panel, the insistence on these restrictions is likely to trigger retaliatory measures by the U.S. government,” GCMA said in a recent report, according to Reuters.

Mexico, the birthplace of modern corn, prohibited the commercial planting of GM corn strains in 2022 and, in 2023, officially banned GM corn for human consumption.

U.S. corn producers and trade officials objected, arguing to the trade-dispute panel that the decision to ban GM corn for human consumption could open the door to further restrictions.

Sheinbaum responded to the ruling, saying, “We are going to reverse this decision … in February, [Congress] will legislate … that transgenic corn cannot be planted … and that Mexico’s biodiversity must be protected.”

The bill addresses Mexico’s long-held fear that GM corn poses the risk of genetic contamination to Mexico’s wide range of native corn varieties. The text of the reform brands native corn as “an element of national identity” and bans GM corn from being planted in Mexico.

“Any other use of genetically modified corn must be evaluated … to be free of threats to the biosecurity, health and biocultural heritage of Mexico and its population,” the bill specifies.

Although scientists and Mexico’s agricultural industry support the reform, some groups argue it does not go far enough.

On Jan. 26, the magazine Proceso reported that the food sovereignty organization Sin Maíz No Hay País (Without Corn There is No Country), wrote a letter to Sheinbaum arguing that her reform was “insufficient” and a “regression.”

The organization proposed using the term “cultural biodiversity” rather than “symbol of national identity,” saying the former has broader connotations.

With reports from Infobae, El País, Canal del Congreso, Reuters and Proceso