Farmers harvest a sugar beet crop in Gilcrest, Colo. Matthew Staver/Landov hide caption

itoggle caption Matthew Staver/Landov

Genetically modified to be enriched with beta-carotene, golden rice grains (left) are a deep yellow. At right, white rice grains. Isagani Serrano/International Rice Research Institute hide caption

itoggle caption Isagani Serrano/International Rice Research Institute

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

Protesters demonstrate against the production of genetically modified food in front of a Monsanto facility in Davis, Calif., in March. The local protest was not specifically about labeling. Randall Benton/MCT /Landov hide caption

itoggle caption Randall Benton/MCT /Landov

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