The first genetically modified (GM) crop was commercially approved and released into the environment 20 years ago. From the beginning, some of us have been warning repeatedly of hidden dangers from the unintended horizontal transfer of GM DNA (transgenes). A comprehensive review  Gene Technology and Gene Ecology of Infectious Diseases, ISIS scientific publication) and successive updates were submitted to the World Health Organization (WHO) and regulatory agencies in the US, UK and European Union (see  Ban GMOs Now, ISIS Report); all to no avail.
The position taken by regulators and their scientific advisors today is perhaps best represented in a recent publication  with lead author Kaare Nielson at Norwegian University of Science and Technology, who both advises Genøk-Centre for Biosafety and serves as member of the EFSA (European Food Safety Authority) GMO panel.
The paper, entitled “Detecting rare gene transfer events in bacterial populations”, recognizes that horizontal gene transfer is part of the risk assessment for GMOs, and that the large-scale cultivation of GM-plants on more than 170 m ha worldwide results in “multitudinous opportunities for bacterial exposure to recombinant DNA and therefore opportunities for unintended horizontal dissemination of transgenes.”