A. If there are closely related species in the wild or in nearby crops, then pollen from a GM crop can pollinate another plant, thereby spreading its genetically engineered traits. There’s been research, for example, documenting the spread of transgenic corn genes into native corn species in Mexico. This is particularly troubling because many native and wild relatives of corn grow in Mexico and such cross-pollination could threaten the genetic biodiversity of corn, an important food crop around the world. Here in the U.S., organic farmers have filed a lawsuit against the USDA for allowing the planting of GM sugar beets, because the GM traits could potentially spread into closely related organic crops, such as chard and table beets, voiding their organic status. Another environmental issue is the increase in chemical use. Between 1994 and 2005 there was a 15-fold increase in the use of Roundup, an herbicide produced by Monsanto—which is also the world’s leading producer of GM seeds. About 80 percent of GM crops are herbicide-tolerant, so farmers can use far more herbicides on their crops and not kill them. If you’re going to engineer a crop to resist a weed-killer that just invites the use of herbicides.