Snow says that there is no evidence so far for negative effects. And she expects that if the transgenes now in use drift to other plants, they will have neutral or beneficial effects on plant growth. In 2003, Snow and her colleagues showed that when Bt sunflowers (Helianthus annuus) were bred with their wild counterparts, transgenic offspring still required the same kind of close care as its cultivated parent but were less vulnerable to insects and produced more seeds than non-transgenic plants. Few similar studies have been conducted, says Snow, because the companies that own the rights to the technology are generally unwilling to let academic researchers perform the experiments.
In Mexico, the story goes beyond potential environmental impacts. Kevin Pixley, a crop scientist and the director of the genetic resources program at the International Maize and Wheat Improvement Center in El Batan, Mexico, says that scientists arguing on behalf of GM technologies in the country have missed a crucial point. “Most of the scientific community doesn’t understand the depth of the emotional and cultural affiliation maize has for the Mexican population,” he says.
Tidy stories, in favor of or against GM crops, will always miss the bigger picture, which is nuanced, equivocal and undeniably messy. Transgenic crops will not solve all the agricultural challenges facing the developing or developed world, says Qaim: “It is not a silver bullet.” But vilification is not appropriate either. The truth is somewhere in the middle.