Americans overwhelmingly support labeling foods that have been genetically modified or engineered, according to a New York Times poll conducted this year, with 93 percent of respondents saying that foods containing such ingredients should be identified. Three-quarters of Americans expressed concern about genetically modified organisms in their food, with most of them worried about the effects on people's health. Thirty-seven percent of those worried about G.M.O.'s said they feared that such foods cause cancer or allergies. Among those with concerns, 26 percent said these foods are not safe to eat, or are toxic, while 13 percent were worried about environmental problems that they fear might be caused by genetic engineering. Nearly half of Americans said they were aware that a large amount of the processed or packaged foods they now buy at the grocery store contains genetically modified ingredients. Overall concern was higher among women than men, perhaps not surprisingly, as more women identify themselves as the principal grocery shopper in the household. Americans were almost equally divided about eating genetically modified vegetables, fruits and grains, with about half saying they would not eat them. They were even less comfortable about eating meat from genetically engineered animals: three-quarters said they would not eat G.M.O. fish, and about two-thirds said they would not eat meat that had been modified.