French scientists recently completed a study on the long-term effects of eating genetically modified foods. Turns out chemicals only need to be proven to be 'safe' in test animals for 90 days. This study found some upsetting long-term consequences from GM foods, and the pesticides used on them. http://www.naturalnews.com/037249_gmo_study_cancer_tumors_organ_damage.html
For a slightly different take on the study, including pointing out some of its weaknesses, check out the BBC's coverage
And, last but not least, here's the study itself if you want to check it out.
Dr. Dielle Raymond, ND