Ongoing Debate: The Prohibition of GMO Corn in Mexico

"Maíz transgénico”, also known as genetically modified organisms (GMO), has been genetically modified to express agriculturally desirable traits, such as pest resistance or herbicide tolerance, by introducing genes from other organisms.  

• At the beginning of his term in 2018, President Andres Manuel López Obrador (AMLO) made a commitment to ban “maíz transgénico” in Mexico and enacted different actions to prohibit its use for human consumption.  

• On September 30, 2024, the Constitution was amended to acknowledge the importance of the agricultural traditions of Indigenous and Afro Mexican communities, particularly native corn, which is considered an essential element of the country’s biological and cultural heritage. Throughout history, corn has not only been a staple food for Mexicans but also a significant cultural symbol. In Mexico, 64 different varieties of corn are cultivated, 59 of which are native. From cultural, social, and nutritional perspectives, it remains one of the country's most essential crops. 

• These reforms are rooted in the recognition of the importance and significance of corn in Mexico. As the foundational food and key ingredient of Mexican cuisine, traditional Mexican cuisine was inscribed as an Intangible Cultural Heritage of Humanity by UNESCO in 2010. Mexico is home to the world´s greatest genetic diversity of corn, and safeguarding this diversity has become a national responsibility to ensure its preservation for future generations. 

• In December 2024, a panel under the United States-Mexico-Canada Agreement (USMCA) concluded that Mexico’s prohibition on the import of GMO corn violated the international treaty between the United States, Canada, and Mexico. The panel explained that there was insufficient scientific evidence to sustain the decision.

• In response, current President of Mexico Claudia Sheinbaum proposed a constitutional reform to address the panel’s decision. On January 23, she submitted the proposal to Congress to prohibit the planting of GMO corn in Mexico, citing the need to protect the genetic diversity of the plant.  
• Meanwhile, Mexico is complying with the panel’s resolution and has withdrawn the ban on the import of genetically modified varieties of corn. 

• Mexico’s Constitution guarantees the right to a healthy environment, obligating the state to preserve and restore ecological balance. It also ensures access to nutritious, sufficient, and quality food. The Constitution further asserts the state's authority over natural resources, committing to their sustainable use and preservation for future generations. 
• The recent constitutional reform approved under President Sheinbaum declares corn a symbol of national identity and mandates that the state ensure the cultivation of GMO-free corn within Mexico’s borders. The reform establishes a constitutional prohibition on GMO corn, stating: “Corn is an element of national identity whose cultivation must be free of GMOs, prioritizing its agro-ecological management.” It further stipulates an explicit ban, affirming that “the optimal use of land will be free of crops and seeds for the sowing of GMO corn.” 
• On Monday, March 17, the reform was published in the Federal Registry, establishing that as of the decree’s entry into force, all provisions that contradict its content, whether found in secondary laws, regulations, agreements, or any other administrative normative provisions, will be revoked. 

• Mexico is the largest importer of US yellow corn, most of which is GMO corn, primarily used to feed livestock such as cattle, pigs and chickens, because Mexico does not grow enough feed corn. In contrast, corn for human consumption in the US is almost entirely domestically grown white corn, although corn flour snacks or other processed products may contain GMO corn.¹ 
• The US is concerned that these restrictions could lead to a significant loss of its largest export market for corn, potentially triggering further restrictions that could harm the trade relationship between the two countries. US officials argue that the scientific consensus supports the safety of GMOs, while Mexican authorities contend that US officials have been unwilling to collaborate in investigating the health implications of GMO corn.²