*Mexico’s President Claudia Sheinbaum has announced plans to introduce changes to the constitution which would prohibit the cultivation of genetically modified (GM) or biotech corn in Mexico. The move, which is in line with a proposal put forward earlier by Sheinbaum’s mentor and predecessor Andrés Manuel López Obrador (2018-2024), follows a decree signed on 20 January by Clara Brugada, the mayor of Mexico City (CDMX), who like Sheinbaum is from the Movimiento Regeneración Nacional (Morena) party, which declares CDMX to be a territory “free of production of genetically modified corn”. Sheinbaum’s latest announcement comes as a trade dispute panel set up under the US-Mexico-Canada Agreement (USMCA) ruled in December that Mexico’s ban on imports of genetically modified corn violates the USMCA. The USMCA panel was ruling on a dispute requested in August 2023 by the US in response to a decree issued by López Obrador which included a ban on biotech corn in tortillas and dough. The US argued that Mexico’s stance is not rooted in science and would negatively impact US corn farmers and producers.