I'd come to Mexico to investigate the ongoing controversy over the proposed introduction of genetically modified (GM) maize into the birthplace of this important global food crop. The issue was hot, because last October a Mexican judge had issued an injunction halting all experimental and commercial planting of GM maize, a process that was well underway in six northern states. The ruling cited the need for precaution to ensure that Mexico's rich diversity of maize varieties were protected from inadvertent "gene flow" from GM maize.