A new website, GMOSeralini.org, is disputing criticism of a study that found that genetically modified (GM) foods damaged the long-term health of rats. The site is run by scientist and citizen supporters of a study by Prof Gilles-Eric Séralini showing that rats fed GM maize and small amounts of the RoundUp pesticide used on it incurred severe organ damage and increased tumors. Opponents argue that the study’s rats were tumor-prone and that the study’s sample size was too small, while GMOSeralini.org’s press release accused scientists critical of the study of having ties to GM food companies, and says the same rats were used in Monsanto’s internal safety study on GM foods. The study’s defenders have started a worldwide Avaaz petition calling for independent long-term safety tests to be carried out on GM products.