Mexico has taken the last step toward finalizing rules that will allow genetically modified crops to be planted in the country. That has many farmers in the so-called birthplace of corn worried that GM varieties could contaminate their fields. Under the rules, GM corn wouldn’t technically be allowed in certain areas of Mexico considered “centers of origin” for unique corn plants, but critics nevertheless remain concerned for crop biodiversity. “This is a step in the government’s intention to bow to pressure from Monsanto to allow the contamination of Mexico’s native corn,” said farmer Victor Suarez.