Trying to understand the debate over Genetically Modified Organisms (GMOs) is a bit like trying to pick up mercury. It seems solid enough, but try to grasp it and it slips away. Critics of GMOs might draw another parallel as well. Considering how pervasive GMOs are and yet how little we know about them, using them incautiously today could be inviting widespread harm tomorrow -- just as toxic mercury contamination over the years still poisons our food chain today.

One reason the GMO debate is difficult to grasp is that the term "GMO" refers to genetic manipulation of a wide variety of plants and animals. Scientists have been manipulating genes for years to modify plants. What's new is the unprecedented increase in both the quality and quantity of experimental gene manipulation and the sheer volume of GMOs being introduced into the environment.

Consumers are most likely to encounter GMOs in foods (primarily plants and produce) that have been genetically altered to make them resistant to pests or pesticides. Gene manipulation can also be used to add vitamins to a food, or change its characteristics, such as color and flavor.

Both supporters and critics have engaged in name-calling. As Dan Glickman and Vin Weber noted in the International Herald Tribune on July 1, "[anti-GMO] Europeans talk of 'Frankenfoods' and the [pro-GMO] U.S. calls Europeans 'Luddites.' "

In their article, Glickman, a former congressman, and Weber, a Clinton-era bureaucrat, define the dispute in simple terms: "The United States has repeatedly pointed out that there is no evidence that GM foods currently on the market are harmful to human health or the environment. The Europeans counter that without extensive, long-term monitoring and research there is little proof that [GM foods] will not cause harm." This simplification correctly highlights safety concerns, but ignores the evidence that GM foods can be and have been harmful.

Agribusiness corporations often obscure safety concerns. Their demands for expedient "free trade" often drive the debate, forcing safety to take a back seat. U.S. chemical and seed giants like Dow, DuPont, Monsanto and Archer-Daniels-Midland are pressuring the U.S. government to force open European and other foreign markets, while Europe's own multinationals -- Novartis, Zeneca-Astra, Nestle and Bayer -- hope to dominate local sales and grab a larger piece of markets in Asia, Africa and South America.

U.S. corporations have been particularly keen to bring down a European Union moratorium that for five years has banned approval of new genetically modified organisms. This month the Americans got their wish -- well, sort of.

On July 3, the European Parliament approved two laws lifting the moratorium. To the horror of corporate America, however, the new laws will require that all GM foods be labeled. "Under the new regime all products containing more than 0.9 percent [GMOs] will be labeled as GM products. Labeling will also be extended to animal feed and all products . . . containing highly refined soya or maize oil. The laws will force farmers, manufacturers and distributors to collect and retain detailed information on the presence of GMOs in any product making its way through the commercial chain," reported the Financial Times on July 2.

In place of the ban, importers now face a costly labeling labyrinth. "U.S. farmers say the laws will do nothing to open the EU market . . . because the elaborate tracing provisions are impossible to meet without a costly effort," notes the Financial Times.

In contrast, European firms seem unfazed by the new laws. "In Europe there is a clear trend among consumers that they want to avoid the products with GMO labels, so there is clear pressure on producers to make sure they that have no GMOs and so will not have the label," an official of Dutch-based Ahold told Reuters. Ahold is the world's third largest food retailer.

In Europe, apparently, businesses still believe "the customer is right." Opinion polls show "70 percent of Europeans do not want GM food and 94 percent want to be able to choose whether or not they eat it," according to a report in The Guardian on July 2.

In the U.S. as well, a 2001 ABC News telephone poll found that 93 percent of Americans want labeling of GM foods. The same poll found that 52 percent believe genetically altered foods are unsafe. Nevertheless, the Bush administration and corporate America are working to ensure that Americans have neither the information nor the choice.

In the meantime, millions of hectares of farmland worldwide are now planted with GMOs, and more than half the products Americans find in stores today contain GM ingredients. Advocates of GMOs claim that such widespread use without calamity is proof of safety. Critics, on the other hand, are concerned that incautious use of GMOs in food and livestock feed is inviting tragedy along the lines of mad cow disease and the consequences of DDT and Thalidomide use.

Because genetic engineering is a relatively young science, little research has been done to determine the effects of genetically engineered plants on local ecosystems. Nor has sufficient scrutiny been given to the long-term effects of GMOs on livestock and humans, particularly on reproductive health.

Specific health concerns include allergic reactions in farmers and consumers; the creation of new toxins harmful to humans and livestock; and concerns that genetic engineering might lead to antibiotic resistance and a resurgence of infectious diseases. Other problems are: increased pesticide use (some genetically engineered crops are designed to be sprayed with heavier doses of chemicals); genetic contamination of the environment by GM plants or animals, particularly fish, that encroach on indigenous species and destroy balanced ecosystems; unforeseen harm to insect, bird and animal species, including death and mutations; concerns that modified genes in one species may "jump the species barrier" into other animals and plants; and, unknown impacts on soils and microbial ecosystems.

Perhaps Pandora's Box has already been opened, but it is never too late to intensify research and heighten caution. Europe's labeling system is a step in the right direction, but Europe, Japan and, above all, North America still have a long way to go before consumers can be confident -- and legally guaranteed -- that what they buy is what they want to eat.

Glickman and Weber call for a "trustworthy, credible and effective regulatory system," but this is only the first step. Such a system needs to be nationally and internationally codified and enforced, and can only be realized with full disclosure and transparency at all levels, from producers to corporations and governments. Costly, yes, but corporations must make the investment in their -- and our -- future.

In the meantime, my family will continue to eat organic whenever possible. Sure, it's more expensive, but it's a vote for long-term sustainable agriculture. We get healthier, safer food, and our money supports farmers who work hard to care for the earth, avoiding insecticides, herbicides, synthetic fertilizers and new GMO seed. For us, that's a price worth paying.