The foes of genetically modified food have this one huge issue that won't go away: the science keeps going against them.

The latest example took place late last month, when a prominent journal withdrew the one study that seemed to show a definitive link between health problems and food whose genetic mix has been altered to make it more resistant to pests or grow under less-than-ideal conditions.

And what a study it was, replete with disturbing photographs splashed across the Web: White lab rats that had feasted on GM corn developed grotesque, swollen tumors. Here was hard proof that bio-engineered food was a menace to anyone or anything that consumed it.

Then again, maybe not. It turns out that the rats in question were a strain that often develop tumors within their two-year lifespan, which covered the duration of the study. That made it impossible to determine which tumors were routine and which might have been caused by the GM corn. Making matters worse, the sample size was too small to meet standards used to establish statistical significance. Under a deluge of criticism from both independent and national scientific organizations, the journal that published the study, Food and Chemical Toxicology, issued a retraction.

That should have settled it, right? Maybe if this were a normal scientific controversy. But this is GM food and, like climate change, it's a topic that doesn't seem subject to the normal rules of scientific inquiry. That might include the molecular biologist who headed the study, Gilles-Eric Seralini of Caen University in France and a longtime foe of GM foods. Instead of voluntarily withdrawing the study after its shortcomings were pointed out by other scientists, he threatened to sue the journal and accused those who disputed his findings of having conflicts of interest.

And he had plenty of supporters, including the European Network of Scientists for Social and Environmental Responsibility, which denounced the retraction and claimed the agricultural industry had strong-armed the editorial board of the journal. Naturally, posts on the Internet suggested the anti-Seralini campaign was the handiwork of Monsanto Co., the largest producer of GM seeds.

As for the study, rats were fed corn modified to resist the Monsanto-made herbicide Roundup. Farmers can apply it to kill weeds without damaging GM crops. Chief among Seralini's findings was that female rats were two to three times more likely to die than rats in a control group. This caused all sorts of people — not to mention politicians — to freak out.

In response, Russia and Kenya either barred or placed holds on imports of GM crops and France's prime minister said his country would press for a European ban on Roundup-resistant corn if the results were confirmed. The study even got some air-play in last year's unsuccessful ballot initiative in California to require labeling of food containing GM ingredients.

Yet Seralini's methods looked unorthodox from the get-go. Before the study was released, he allowed select journalists to have advance copies with a bizarre condition: if they showed it to third parties they would be subject to financial penalties that could cost millions of euros. This, of course, made it impossible for peers to challenge his work before publication.

Seralini had more ambitious plans as well: At the time the study was released in September 2012, he said he planned a book and a movie about his research. Those, no doubt, are on hold.

So where does this leave the debate about GM foods? Yes, Big Ag, Monsanto first and foremost, won this battle. But it was far from satisfying. A healthy measure of blame has to be laid on the journal that published the study. Instead of citing fraud or intentional misrepresentations — — the usual reasons for a retraction — — it simply said the findings were inconclusive. That leaves you wondering why the study even made it into print in the first place.

Examining the safety of GM foods is a worthy endeavor. It's the only way that the unsubstantiated claims made by its opponents will ever be put to rest — — or that their concerns will finally be confirmed, however unlikely that seems. Too bad Seralini's contribution was to add only heat to the discussion and no comparable amount of light.