 From VOA Learning English, this is the health report in special English. Scientists are criticizing a study that said laboratory rats developed tumors after they ate genetically modified corn. The research appears in the journal Food and Chemical Toxicology and includes pictures of rats with large tumors. The study said the animals developed the growths after two years of being fed genetically changed maize. Gilles-Éric Serralini was the lead author for the research paper. He is with the University of Caen in France. He says genetically modified or GM foods have not been studied carefully. However, several French scientific organizations and the European Food Safety Authority dispute the study. One genetic expert with the National Academy of Sciences in the United States says the rats in the study were genetically predisposed to form tumors. Alison Van Eanam is with the University of California, Davis. She suggests that the study was an attempt to scare the public. She said, I think it was a cynical ploy to exploit the scientific process to create fear in the minds of consumers. Even some opponents of GM food agree there were problems with the study methods. Michael Hansen with the Group Consumers Union says there should be more long-term studies and more rules for GM foods. Safety studies or assessments are voluntary when companies ask the government to approve new GM crops. These assessments often include 90-day rat feeding tests. This is the international standard. Experts say longer studies have not found major problems. For VOA Learning English, I'm Alex Villarreal.