A month or two ago, there was a study of rats feed GE corn in France. It was widely criticised at the time. Recently it's started being referenced in scary pictures the flick through my book of face feed, upon which I commented. In the comments I was asked to elaborate on my position that a seriously flawed study, which I'm going to do there, because facebook comments are an annoying place to try and lay out something like this. So apologies to those of you for whom this is a rehash.
The study was touted as being a long term (2 year) study as opposed to the more common 90 day test. On the face of it, this sounds like a good thing and it could very well have been. If you were going to do a long term study and report on the incidence of tumours though, I would suggest not using a strain of rats (Sprague-Dawley rats, a particular strain of lab rat) that are highly prone to get tumours after 2 years anyway - that's living a life without being experimented on. Something that has been known about for many, many years.
On top of that the number of rats used in each group was woefully small - 10 rats in each group. This brings a large amount of statistical variability into play. The paper linked to in the last paragraph gave 86% chance of tumour development for males and 72% for females - without treatment of any kind. If you take 10 rats from a population, getting the results that Seralini did due to chance alone is very very high. To be able to say that any deaths/tumours were the result of the rats diet of GM and GM+roundup corn they would have had to have much, much larger numbers of rats per sample, somewhere north of 60. The best discussion of why the Seralini paper was statistically rubbish, is from Andrew Kniss at weed control freaks. For a detailed discussion of the myriad of other problems with the study, Emily Willingham has a pretty good overview.
The picture the started all this off was using a Russian ban of GM corn as an exemplar. I opined that the ban was political and not based on the science. This I may very well be wrong about. The paper was widely and rightly criticized before the Russian ban though, anyone making a decision based on it's results, especially at the international trade level would have been being disingenuous at best. Which leads me to believe that there was a political or economic motive being it, with the study being used as an excuse.
I've said it before and I'll say it again. GE is not inherently bad. It's a tool to be used when and where appropriate. I've got no problem with people having problems with Monsanto's business practices but Monsanto is not GE and GE is not Monsanto. GE can be used to prevent dietary deficiencies, create drought resistant crops or possibly one day provide sustainable fuels and plastics. Sure we should study the effects GE food has on people, just as much as we should study the effects that non-GE food has on us. The Seralini study was seriously not the way to do it though.
And that's without mentioning the unethical abuse of journalists and press embargoes used to hype the paper to the mainstream press.