BS. total and unadulterated. IMO, you should take most of these sorts of reports, in the popular media, with a pound of salt.
They paint 'GMO' with a broad brush, like they're all the same - but they're not. Some have the Bt gene inserted to confer resistance to attack by corn borers, earworms, other insect pests, some have the Roundup-resistance gene, some have inserted genes to confer greater drought resistance, etc.
If you try to Google up info, about all you'll get are organic food/left-wing kook sites - that either don't really give any specific info, no real documentation - just anecdotal reports - and all parrot one another. When you look at one FoodNation/OrganicFood/ActivistPost site after another, and they're all essentially a repeat of the identical 'talking points', I have a hard time giving 'em much credence.
As best I can tell from searching the scientific literature, the anti-GMO folks are keying in on the Cry1Ab protein, an insecticidal protein produced by
Bacillus thuringiensis, which is coded for by the gene inserted into Bt corn/soybeans. Cry1Ab is degraded in the mammalian stomach - it's only effective against specific insect larvae - and, the 'organic' folks use Bt out the wazoo, anyway - it's one of their 'approved' insecticide. Additionally, the methods by which some researchers have used in purportedly identifying Cry1Ab in human blood/fetuses/placenta has been debunked as not valid.
There was a French paper which was released - and trumpeted widely by the anti-GMO crowd - claiming that Roundup-Ready crops and glyphosate were causing cancer in laboratory rats/mice. It was eventually even debunked by the EU, due to flaws in experiment design, and refusal by the authors to release pertinent information, etc.
http://iphone.france24.com/en/20121128- ... ize-cancer
Note: if you allow normal laboratory rats to live out their entire lifespan, a significant number of them develop tumors of one kind or another, regardless of whether they're fed RR corn or crops sprayed with glyphosate. http://www.ncbi.nlm.nih.gov/pubmed/1444814