Séralini's rat study claimed GMOs caused tumors — and it was retracted, then republished

In September 2012, Gilles-Éric Séralini, a French molecular biologist at the University of Caen, published a study in Food and Chemical Toxicology claiming that rats fed genetically modified (GMO) NK603 corn developed tumors and organ damage at significantly higher rates than control groups. The study was accompanied by dramatic photographs of tumor-bearing rats.

The scientific community responded with near-universal criticism. The study used a rat strain (Sprague Dawley) known for high spontaneous tumor rates, had too few animals per group for statistical significance, and lacked adequate dose-response analysis. In November 2013, the journal retracted the paper, citing inconclusive results.

In 2014, the study was republished in Environmental Sciences Europe, a journal with a different editorial stance. The case became a flashpoint in the GMO debate, with Séralini's supporters arguing the retraction was politically motivated and his critics arguing the science was irredeemably flawed. The case illustrated how a methodologically weak study can become a powerful narrative when it confirms existing beliefs, and how the retraction process cannot undo the damage of a viral headline.