Mexico Moves to Ban GMO Corn in Its Constitution: Impact and Challenges

A Landmark Reform to Protect Native Corn

The Mexican government has proposed a constitutional amendment to ban the cultivation of genetically modified (GMO) corn nationwide. President Claudia Sheinbaum introduced the initiative in January 2025, aiming to modify Articles 4 and 27 of the Mexican Constitution.

The proposal seeks to enshrine corn as a fundamental element of national identity and establish the state’s obligation to protect native corn from genetic modification. The revised Article 4 would recognize corn as a cultural heritage that must remain free from GMOs, while Article 27 would mandate the promotion of agroecological farming methods and prohibit the use of genetically modified seeds.

This move aligns with Mexico’s longstanding policy of safeguarding its 59 native corn varieties, arguing that transgenic contamination could threaten biodiversity, cultural traditions, and food sovereignty. The proposed reform responds to ongoing legal and trade disputes related to GMO corn, reinforcing the government’s commitment to protecting its agricultural heritage.

Background: Mexico’s Stance on GMO Corn

As the birthplace of corn, Mexico has historically taken a cautious approach to genetically modified crops. In 2005, the country passed the Biosafety Law on Genetically Modified Organisms (GMOs), establishing strict controls on GMO releases.

In 2013, a federal court issued a nationwide injunction halting GMO corn cultivation due to concerns about genetic contamination. Despite pushback from agribusiness, this legal blockade has remained in place, effectively preventing commercial planting of GMO corn while courts continue to evaluate the long-term risks.

Under the previous administration, Mexico intensified restrictions on GMOs. In 2020, the government passed the Federal Law for the Promotion and Protection of Native Corn, aiming to preserve traditional maize varieties. Additionally, a 2020 presidential decree banned the gradual use of GMO corn in Mexican agriculture, with a complete phase-out initially set for 2024.

These measures triggered strong opposition from biotechnology companies, commercial farmers, and international trade partners, particularly the United States. The scientific community remains divided, with some experts arguing that Mexico’s restrictions are based on precaution rather than conclusive evidence of harm from GMO crops.

Economic and Trade Implications

Potential Impact on Mexican Farmers

For small-scale farmers and indigenous communities, the ban is seen as a victory. Protecting native corn ensures the survival of traditional farming systems, prevents genetic contamination, and safeguards Mexico’s agrobiodiversity.

However, large-scale commercial farmers warn that the prohibition could limit access to modern agricultural technology, potentially reducing crop yields and putting Mexican producers at a disadvantage compared to U.S. farmers, who widely use GMO corn for increased productivity.

Without access to genetically modified seeds, Mexico’s ability to increase domestic corn production—especially for animal feed—could be restricted. The government argues that traditional breeding and agroecological practices can improve yields without relying on genetic engineering.

U.S.-Mexico Trade Relations and the USMCA Dispute

Mexico imports approximately 17 million tons of U.S. yellow corn annually, primarily for livestock feed, making it one of the largest buyers of American corn. Most of this imported corn is genetically modified.

Although the proposed reform does not explicitly ban GMO corn imports, it raises concerns about future trade policies. In 2023, the United States challenged Mexico’s restrictions under the United States-Mexico-Canada Agreement (USMCA), arguing that they violate trade obligations by not being based on scientific evidence.

In December 2024, a USMCA dispute panel ruled in favor of the U.S., stating that Mexico’s measures were inconsistent with the agreement. While Mexico has since amended its policies to allow GMO imports, enshrining the ban in the Constitution could reignite trade tensions and potentially lead to tariffs or retaliatory measures from the U.S.

If Mexico were to extend the ban to imported GMO corn in the future, it could trigger a severe trade conflict, as the U.S. has warned of significant economic repercussions, including potential sanctions.

Key Reactions: Supporters and Critics

Support from Environmental and Agricultural Advocacy Groups

Organizations advocating for small farmers and environmental protection, such as Greenpeace and the National Campaign “Without Corn, There is No Country,” strongly support the ban. They argue that:

• GMO crops pose risks to native corn through cross-pollination.
• Protecting biodiversity is crucial for long-term food security.
• The Mexican government has a responsibility to preserve indigenous agricultural traditions.

Opposition from Agribusiness and Trade Partners

On the other hand, agricultural associations and biotechnology companies oppose the ban, citing:

• Reduced competitiveness for Mexican farmers.
• Potential disruption to supply chains that rely on GMO corn.
• Increased costs for industries that depend on imported corn, such as livestock and food production.

The United States and Canada have voiced concerns, emphasizing that Mexico’s policies must align with trade commitments under the USMCA and be supported by scientific risk assessments.

Legal Challenges and the USMCA Conflict

By elevating the GMO corn ban to constitutional status, Mexico could face new legal battles at both the domestic and international levels.

• Under Mexican law: A constitutional amendment would override existing regulations and require extensive legislative adjustments, potentially leading to legal challenges from affected industries.
• Under USMCA rules: The U.S. and Canada could argue that the prohibition violates trade agreements, leading to another dispute settlement case.

While Mexico could claim that the ban is a sovereign decision to protect cultural heritage, international trade bodies typically require restrictions on agricultural biotechnology to be based on scientific risk assessments.

Possible Future Scenarios

1. Controlled Implementation with Trade Compliance
   • Mexico maintains the constitutional ban on GMO cultivation but allows GMO corn imports to avoid USMCA penalties.
   • The government invests in boosting domestic non-GMO corn production through agroecological methods.
   • Trade tensions remain manageable as long as import policies do not change.
2. Expansion of the Ban and U.S. Retaliation
   • Mexico moves to prohibit GMO corn imports, triggering a trade dispute with the U.S.
   • Retaliatory tariffs could impact Mexican agricultural exports.
   • U.S. corn producers face economic losses, escalating diplomatic tensions.
3. Scientific and Trade Cooperation
   • Mexico and the U.S. negotiate a compromise, allowing non-GMO segregated corn imports while maintaining domestic planting restrictions.
   • Joint research initiatives assess the environmental impact of GMO crops to create policies aligned with both trade and biodiversity protection.
4. Political or Technological Shifts
   • Future Mexican administrations could modify or repeal the ban if economic pressures increase.
   • Advances in gene-editing technology (such as CRISPR) may create alternatives that bypass the restrictions on traditional transgenics.

A Defining Moment for Mexican Agriculture

Mexico’s move to constitutionally ban GMO corn reflects its commitment to preserving agricultural heritage and biodiversity. However, the decision carries significant trade and economic risks, particularly in its relationship with the United States.

The challenge lies in balancing national food sovereignty with international trade obligations. While Mexico aims to protect its native corn varieties, it must navigate complex economic and legal landscapes to avoid unintended consequences for its farmers and consumers.

The coming months will determine whether Mexico can implement this policy without triggering trade retaliation or economic instability. The future of Mexican agriculture now hinges on how well the government can sustain its commitment to biodiversity while maintaining economic stability and international cooperation.