There are other risks involved with genetic engineering. Genes can travel to nearby, related plants on their own. This is called gene flow. In 1996 gene flow was discovered to be much more common that previously thought. According to Science magazine, many ecologists say it is only a matter of time before an engineered gene makes the leap to a weedy species, thus creating a new weed or invigorating an old one.
Most people are opposed to genetic engineering.
Of course there is resistance to this because the GM companies believe correctly that the majority of people would not buy GM food if it were clearly labelled. In the U.S., every other food carries a label listing its important ingredients, with the remarkable exception of genetically engineered foods. There is another side to this difficulty in identifying what has been GM modified. If GM foods can not be identified this will prevent epidemiologists from being able to trace health effects, should any appear, because no one will know who has been exposed to novel gene products and who has not. This also applies to GM crops fed to livestock.