In November, California voters will decide on a ballot initiative that would require labeling of all foods containing ingredients from genetically modified crops. The initiative made it to the ballot after almost 1 million Californians signed a petition in favor of it—nearly double the 504,760 signatures needed under the state’s proposition rules. The campaign that organized the push to get the measure on the ballot focused on possible health effects of GMO foods.

http://www.motherjones.com/tom-philpott/2012/05/california-gmo-labeling