Cathleen Enright, executive director of the Council for Biotechnology Information, has answered a similar question on GMO Answers. This response, which addresses mandatory labeling, is available here and excerpted below.
We are often accused of being against labeling. We are not. If any food, including GM food, presented a safety risk to a certain population―for example, those allergic to a food ingredient―we most certainly would support a mandatory label on that food alerting consumers to this concern. But this is simply not the case.
There is no evidence linking a food-safety or health risk to the consumption of GM foods. There are hundreds of independent studies that demonstrate this (check out independent studies at Biofortified), in addition to determinations from scientific and regulatory authorities around the world that GM foods on the market are as safe and nutritious as their non-GM counterparts (see FDA information here). A few studies have asserted that such a risk exists, but each of these studies has been found not to be credible by the global scientific community.
We support the right of consumers to choose food that is healthy and nutritious. As believers in GM technology, and having seen the benefits nurture farmers and society alike [check out "GMOs and the Future of Agriculture"], we cannot support a label that conveys to consumers that food made from farmers’ crops grown with our seeds is less safe or nutritious or different from conventional or organic food. We believe a government requirement to label a food “GMO” would do just this.
We also recognize that GM technology is but one tool that will be needed to feed a burgeoning population using less land and fewer resources in the face of increasingly severe weather. The United Nations Food and Agriculture Organization predicts that by 2050 we will need to double our current agricultural production, and 70 percent of that increase will need to come from new, efficient technologies. In this regard, we support any agricultural production method that will help us to achieve global food security by 2050. You will never see us oppose organic farming, for example.
[W]e support voluntary, market-based labeling to promote one type of product over another, including labels for the presence or absence of GM ingredients. Currently, if consumers wish to choose food that does not contain GM ingredients, marketing labels such as “USDA Organic” are being used by food companies to meet their demand.
In this response, excerpted below, Carol Keiser, president of C-BAR Cattle Company, Inc., discusses why mandatory GM labeling might lead to heightened misperceptions and confusion among consumers about the food they purchase.
The purpose of a food label is to help consumers make smart decisions about what to buy and eat. But what if these labels confused people instead of informed them? Or, worse yet, what if labels actually misled consumers?
The dangers of deceptive labeling aren’t a speculative assertion but rather the main point of a paper by Juanjuan Zhang, a marketing professor at the Massachusetts Institute of Technology. "Mandatory disclosure of GMOs in food products lowers consumers’ perceived GMO safety," she writes in "Policy and Inference: The Case of Product Labeling." Zhang’s research reveals that the mere act of labeling food that contains GMOs is deceptive. It causes consumers to suspect that GMOs are dangerous, even though the safety of biotech food is beyond reasonable doubt, as organizations ranging from the American Medical Association to the World Health Organization have determined.
Supporters of the “just label it” movement like to talk about “the right to know.” Yet Zhang’s scholarship shows that consumer behavior is more complicated than a political slogan. Labels possess the power to mislead. That means our lawmakers must mandate them sparingly, and not just because a few special-interest groups want the federal government to help them obtain a competitive advantage in the food market.
Lastly, many people like you want as much information as possible about the food they consume. In this response, Andy Hedgecock, director of scientific affairs at DuPont Pioneer, talks about how an open discussion about GMOs will accomplish more than any label on a product can. An excerpt is included below.
At the end of the day, we believe all labels should be helpful and not misleading for consumers. What I find in the discussions I have is that "helpful" means different things to different people. When it comes to biotechnology, some would find it helpful to know about GM safety, and others are interested in the potential impacts on the environment (including beneficial), perceived corporate control of agriculture or how we make biotech crops and why. In the end, a label will not help answer these questions. But we can. That is why the biotech companies have joined together to create this forum where consumers can ask their questions directly of us―independent scientists, health professionals, farmers and more.