A global positioning receiver on the top of a combine harvester at a farm in Warwick, Md., in June. The equipment uses sensors and computers to help drive the combine along the route where the crops were planted, judge the composition of a crop and generate crop yield reports. Brendan Smialowski/AFP/Getty Images hide caption

itoggle caption Brendan Smialowski/AFP/Getty Images

Wheat grows in a test field at Oregon State University in Corvallis. Some scientists believe that there's a chance that genetically modified wheat found in one farmer's field in May is still in the seed supply. Natalie Behring/Bloomberg via Getty Images hide caption

itoggle caption Natalie Behring/Bloomberg via Getty Images

Crop consultant Dan Steiner inspects a field of corn near Norfolk, Neb. Dan Charles/NPR hide caption

itoggle caption Dan Charles/NPR

Vernon Hugh Bowman, who took his case to the Supreme Court, lives outside the small town of Sandborn, Ind. Dan Charles/NPR hide caption

itoggle caption Dan Charles/NPR

A farmer holds Monsanto's Roundup Ready soybean seeds at his family farm in Bunceton, Mo. Dan Gill/AP hide caption

itoggle caption Dan Gill/AP

Central Illinois corn and soybean farmer Gary Niemeyer readies his genetically modified seed corn for spring planting at his farm near Auburn, Ill. Seth Perlman/AP hide caption

itoggle caption Seth Perlman/AP

People march demanding labels for genetically modified food near the White House in Washington, D.C., on Oct. 16, 2011. Ren Haijun/Xinhua /Landov hide caption

itoggle caption Ren Haijun/Xinhua /Landov

Farmer Alan Madison fills a seed hopper with Monsanto hybrid seed corn near Arlington, Illinois, U.S. A group of organic and other growers say they're concerned they'll be sued by Monsanto if pollen from seeds like these drift onto their fields. Daniel Acker/Landov hide caption

itoggle caption Daniel Acker/Landov