More than half of the corn, soybeans and cotton grown in the U.S. these days starts as genetically engineered seed. The best-known are produced by Monsanto and called "Roundup-Ready," Roundup being the name of an herbicide also produced by Monsanto. The idea is that the GE crops can be doused with Roundup to kill off weeds without damaging the crops themselves.

Well, someone forgot to tell Monsanto that nature is pretty slick about adapting to change: Weeds have evolved resistance to Roundup, requiring farmers to apply great quantities of different herbicides to kill them, which is expensive and dangerous.

All this and more is detailed in a new report from the Organic Center, the Union of Concerned Scientists and the Center for Food Safety, which goes on to reveal that not only must farmers shell out large sums to pay for extra chemicals—the price of the GE seeds has gone through the roof even as their effectiveness declines.