According to a March 21, 2025 report issued by the U.S. Department of Agriculture (USDA)’s Foreign Agricultural Service, the scope of Mexico’s recent ban on the cultivation of genetically engineered (GE) corn is “ambiguous” and may leave the door open to restrictions on corn grain imported for food or feed use in the future. U.S. growers, distributors, and developers of GE plants should carefully monitor Mexico’s implementation of the cultivation ban and potential responses by the United States, particularly as U.S.-Mexico trade issues continue to receive heightened scrutiny under the Trump administration.
Legal Background
In the United States, GE plants and other organisms are jointly regulated by USDA, the U.S. Environmental Protection Agency (EPA), and the U.S. Food and Drug Administration (FDA) consistent with the Coordinated Framework for the Regulation of Biotechnology. This nearly 40-year-old federal policy describes each agency’s regulatory responsibilities under overlapping statutory frameworks. For example, when agricultural crops, such as corn, are genetically engineered to produce pesticidal substances, EPA regulates the substance (known as a plant-incorporated protectant, or “PIP”) under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), USDA regulates the GE plant under the Plant Protection Act (PPA), and FDA ensures that GE products meet applicable food safety standards under the Federal Food, Drug, and Cosmetic Act (FFDCA).
By contrast, a de facto ban on GE corn planting has been in place in Mexico since 2013, and in effect, prohibitions have existed since 1998. In 2023, the Mexican government officially issued a decree mandating that competent authorities revoke and refrain from issuing permits for the release of GE corn seeds in Mexico, as well as authorizations for the use of such corn grain for human consumption. The decree also ordered the gradual elimination of GE corn used in animal feed and industrial uses intended for human consumption.
In August 2023, the United States formally challenged Mexico’s decree under the United States-Mexico-Canada Agreement (USMCA). In a December 20, 2024 decision, a duly established panel agreed with the United States that Mexico’s restrictions were inconsistent with USMCA principles because, among other reasons, the measures were not based on “relevant international standards, guidelines or recommendations.” In compliance with the panel’s decision, Mexico issued an agreement on February 5, 2025, that revoked the relevant portions of the 2023 decree.
New Constitutional Ban on the Cultivation of GE Corn in Mexico
On March 17, 2025, Mexican President Claudia Sheinbaum issued a new decree amending Articles 4 and 27 of the country’s Constitution, which addresses the conservation and protection of native maize varieties.
In relevant part, the amendment establishes that corn grown in Mexico “must be free from genetic modifications produced through techniques that surpass the natural barriers of reproduction or recombination, such as transgenic methods.” While it does not specifically address GE corn grain imports, the amendment provides that “any other use” of GE corn “must be evaluated in accordance with legal provisions to ensure it poses no threat to biosafety, public health, or Mexico’s biocultural heritage and population.” In addition, the amendment mandates federal promotion of traditional agricultural practices — particularly those using native seeds and agroecological methods — through investment, research, and institutional strengthening.
Continued potential for restrictions on imports under the new constitutional ban
While Mexico formally complied with the USMCA panel’s decision by nullifying the prohibitions against the uses of GE corn under the 2023 decree, the new 2025 amendment entrenches anti-GE corn principles in national law and creates a legal foundation that could support future restrictions on GE corn imports. This poses a potential risk of additional regulatory barriers, legal challenges, and renewed trade disputes, particularly if future measures are framed in terms of biosafety, biocultural protection, or food sovereignty, which are now protected goals under Mexico’s Constitution.
Despite not imposing a formal import ban, the 2025 Amendment enshrines a constitutional preference for the exclusion of GE corn from Mexican agriculture and strict oversight of any other uses. This may open the door to more rigorous approval standards on imported GE corn (such as labeling, traceability, or risk assessments) and provide a stronger legal basis for those who seek to challenge import authorizations on constitutional grounds going forward.