Opponents of genetically modified foods just lost a major scientific datapoint for their position after a journal retracted a French study linking altered corn to tumors in rats.

The widely publicized study, published in September 2012 by Food & Chemical Toxicology, had attracted criticism as scientifically flawed even before its retraction late last week. The two-year study by Gilles-Eric Seralini of the University of Caen used only 10 rats for the research—and the species studied is known to develop tumors regardless of its diet.

“A more in-depth look at the raw data revealed that no definitive conclusions can be reached with this small sample size regarding the role of either NK603 or glyphosate in regards to overall mortality or tumor incidence,” said Elsevier, the Dutch company that publishes Food & Chemical Toxicology. in a statement. “Given the known high incidence of tumors in the Sprague-Dawley rat, normal variability cannot be excluded as the cause of the higher mortality and incidence observed in the treated groups.”

In the discredited study, the rats were fed NK103 maize that had been developed byMonsanto (MON) to be resistant to its Roundup herbicide. The study was quickly seized on by groups that opposed genetically modified foods. As the Economistnoted:

“The article was explosive. The French prime minister said that, if its results were confirmed, his government would press for a European-wide ban on NK103 maize. Russia suspended imports of the corn. Kenya banned all GM crops. The article came out two months before a referendum in California that would have required the labeling of all GM foods.”

The journal said it had no evidence of fraud “or intentional misrepresentation of the data.”

Of course, the retraction of a single study can hardly be expected to move public opinion. As Bloomberg Businessweek reported last week, opposition to genetically modified crops has spread across Europe and elsewhere in the world, giving rise to regulations that hamper Monsanto’s multibillion-dollar business selling seeds and licenses to grow genetically altered crops—as well as a new class of unregulated mutant crop rivals.