A widely-criticized study by a French team claiming that genetically modified corn caused laboratory rats to develop tumors has been thoroughly rebutted by an agency of the German government, which said the “study” is full of holes and reaches conclusions that are not supported by the data, which the agency said was inadequate and badly presented.

“The study shows both shortcomings in study design and in the presentation of the collected data,” said Professor Dr. Reiner Wittkowski, vice president of the Federal Institute for Risk Assessment (BFR), an agency of the Federal Ministry of Food, Agriculture and Consumer Protection (BMELV). The agency advises the German federal government and state governments on questions of food, chemical and product safety. “This means that the conclusions drawn by the authors are not supported by the available data,” Wittkowski said.

The study by Gilles-Eric Séralini and colleagues failed to use enough rats in the control group to draw any conclusions and used a strain of lab rats that are known to spontaneously develop tumors when they are going on two years old. Séralini made a point of keeping rats for more than two years.

The author’s presentation of their data was incomplete, the German agency said, making it impossible for outside scientists to assess the results, as required by scientific protocols. The agency said it was requesting complete data from the French team, which has so far refused to comply with such requests.

The agency noted that several studies by the Séralini team have received similar criticism in the past. Read more.