On both scores, then, the risk of bioengineering to the food supply seems to be very slight. GM foods to date seem completely safe.
Are GM crops harmful to the environment?
What are we to make of the much-publicized report that Monarch butterflies might be killed by eating pollen blowing out of fields planted with GM corn? First, it should come as no surprise. The GM corn was engineered to contain an insect-killing toxin (harmless to people) in order to combat corn borer pests. Of course it will kill any butterflies or other insects in the immediate vicinity of the field. What we should focus on is the fact that the GM corn fields do not need to be sprayed with pesticide to control the corn borer. An estimated $9 billion in damage is caused annually by the application of pesticides in the U.S., and billions of insects and other animals, including an estimated 67 million birds, are killed each year. This pesticide-induced murder of wildlife is far more damaging ecologically than any possible effects of GM crops on butterflies.
Will pests become resistant to the GM toxin? Not nearly as fast as they now become resistant to the far higher levels of chemical pesticide we sprayed on crops.
How about the possibility than introduced genes will pass from GM-crops to their wild or weedy relatives? This sort of gene flow happens naturally all the time, and so this is a legitimate question. The answer, it seems to me, is "So what?" What if genes for resistance to Roundup herbicide spread from cultivated sugar beets to wild populations of sugar beets in Europe? Why would that be a problem? Besides, there is almost never a potential relative around to receive the modified gene from the GM crop. There are no wild relatives of soybeans in Europe, for example. Thus there can be no gene escape from GM soybeans in Europe, any more than genes can flow from you to other kinds of animals.
On either score, then, the risk of bioengineering to the environment seems to be very slight. Indeed, in some cases it lessens the serious environmental damage produced by cultivation and agricultural pesticides.
While there seems little tangible risk in the genetic modification of crops, public assurance that these risks are being carefully assessed is important. Agriculture Secretary Dan Glickman announced last summer "an independent scientific review" of how our government's regulatory agencies measure the safety of GM organisms.