(Note: Apologies for any duplication - a database crash at Storify lost the originally published version of this post.)
Were  these anti-GMO research claims about health risks rigged from the start?  French media reports the Seralini research group engaged in bizarre tactics in orchestrating the publicity around their claims in coordination with anti-biotechnology campaigners around the globe.  They used encrypted emails, issued disinformation about a "decoy study," prevented their researchers from making outside phone calls, and required strict non-disclosure agreements preventing journalists from getting independent review of the work from third-party sources.
Even Marion Nestle, a frequent critic of biotech and organic supporter, doesn't believe these claims.  She told the Washington Post, "I can’t figure it out yet. It’s weirdly complicated and unclear on key issues: what the controls were fed, relative rates of tumors, why no dose relationship, what the mechanism might be. I can’t think of a biological reason why GMO corn should do this... I’m skeptical of this study.”

NPR's science reporter Dan Charles reported, "Apart from methodological concerns and personal animosity, there's a deeper reason why scientists give little credence to Seralini's studies. There's a saying in science: Extraordinary claims require extraordinary evidence. For most of the scientists who have been studying the safety of GMOs, it's an extraordinary claim, at this point, to assert that the current generation of genetically modified crops are harmful to human health. There's no apparent reason why that should be trueT; No one has found new toxic substances in these crops. And the giant feeding experiment that's been going on for the past fifteen years — hundreds of millions of Americans consuming GMO ingredients — hasn't produced evidence of harm, either..."

Forbes reports, "The politest thing we can say about the research so far is that they haven’t managed to prove that it is true, no. Scientists working in the area have been, how shall we put this, less than complimentary about some of the methods used..."  Forbes notes one independent academic source pleased to see the Seralini work.   The Statistical Laboratory at the University of Cambridge was "grateful for the authors for publishing this paper, as it provides a fine case study for teaching a statistics class about poor design, analysis and reporting." Adding they "shall start using it immediately.

According to the New York Times, "Dr. Séralini’s work has been questioned before. A review of one of his studies by European authorities concluded that his statistical methods “led to misleading results” and that his study had not raised new issues about the safety of the crop..."  So this time  Dr. Séralini’ is refusing to release the data upon which his study was based to the European Food Safety Agency or other academics for expert analysis or peer review.

This time, Seralini says making his research data available to the European Food Safety Agency - which is responsible for regulating and approving GMOs is "out of the question..."  So, while Seralini and other opponents of biotech are now demanding EFSA use their findings to withdraw approvals of these biotech crops, they are refusing to provide any of the data upon which their findings are based (a standard practice which allows other scientists to replicate results and evaluate the data from the original study).

The BBC reports: "In a move regarded as unusual by the media, the French research group refused to provide copies of the journal paper to reporters in advance of its publication, unless they signed non-disclosure agreements. The NDAs would have prevented the journalists from approaching third-party researchers for comment..."

Why would a scientist whose past research has been funded by Greenpeace do this?  The New Scientist magazine answers,"[Seralini's] research group has long been opposed to GM crops. It claimed in 2010 to have found evidence of toxicity in tests by the GM-crops giant Monsanto of its own Roundup-resistant maize. Other toxicologists, however, said the supposedly damning data revealed only insignificant fluctuations in the physiology of normal rats. French blogger Anton Suwalki, who campaigns against pseudoscience, has a long list of complaints about the group, including what he calls their "fantasy statistics".

Like previous claims, once these new alarms of harm by Seralini and reports about the study (not the actual study details - as noted, Seralini refuses to share those) were published, the list of independent science and academic sources critical of the claims has been fast and furious...