12/14/2010 11:21 am ET | Updated May 25, 2011

Are GMOs Safe?

The most profound innovation to come to many crops in the last generation -- and one of the most widespread -- is genetic engineering. The cultivation of corn and soy today is so scientifically and technologically advanced it would be unrecognizable to a farmer just 40 years ago.

Eighty percent of the 86 million acres of corn planted in the United States today -- as well as 92 percent of the soy, and a good deal of the squash, tomatoes, potatoes, canola and a host of other crops -- comes from genetically engineered, or "GE," seed. Yet despite these crops' ubiquity, 60 percent of Americans don't even know they're eating GE foods.

Even before GE crops were introduced in 1996, debate raged among scientists, farmers, environmentalists and public health officials and academics regarding their safety, with pro and con sides finding little common ground.

"There's now overwhelming evidence that GE foods are unsafe and should never have been introduced," says Jeffrey M. Smith, author of self-published books purporting to show just that.

"Foods derived from biotechnology have been eaten by billions of people without a single documented health problem," counters Sharon Bomer Lauritsen, Executive Vice President for Food and Agriculture of BIO, the lobbying arm of the biotech industry.

It's difficult to find a scientist knowledgeable on the topic who doesn't have financial ties to the biotechnology industry, and it's equally challenging to find an opponent of GE who seems capable of recognizing its potential and doesn't object to the technology per se.

So what's the deal? First, some background:

GE seed contains a gene from a different organism in its DNA, giving the plant it produces desirable traits. Although the biotechnology industry has long promised nutrient-rich and drought- and frost-resistant crops to alleviate hunger and malnutrition among the world's poor (any day now, we're told), the overwhelming majority of GE seed today is modified to tolerate certain pesticides and herbicides -- which in many cases are made by the same companies selling the patented seeds. For instance, St. Louis-based agrochemical giant Monsanto makes Roundup Ready® soy, which is resistant to a pesticide Monsanto sells, enabling farmers to virtually drown their crop in the synthetic chemical. The result is that Roundup® is the most popular agricultural pesticide in the Unites States.

Claims by manufacturers that this makes farming more economical and better for the environment by reducing both the amount of work that goes into the crop, and how much farmers have to spray, are supported by august bodies of science, though some studies place doubt on those findings.

Smith's anti-GMO claim is contradicted by the National Academy of Sciences in the Unites States as well as the UK's leading academy of medical science, the Royal Society of Medicine.

Lauritsen's claim, however, is unsupportable because the absence of evidence is not evidence of absence. Proving safety would require a massive, longitudinal epidemiological study with a control group that has never been exposed to GE foods, which may be well-nigh impossible given that the GE toothpaste is out of the tube: GE seeds migrate into fields of non-GE varieties, so they are virtually impossible to avoid.

Which makes the possible hazards to human health and the environment from GE foods disturbing to some. Alteration of the DNA of GE foods carries the potential to turn them toxic or cause allergic reactions, and their use may actually have led to an increase of spraying of harmful chemicals into the environment.

European nations have even banned GE foods in response to public outcry.

Who is responsible for ensuring that agricultural products are safe for human consumption and the environment?

Should the government commission independent scientific analysis to ensure safety of GE crops to human health and the environment? Should companies be trusted to make their products safe, suffering civil damages if they're later proven otherwise? Or should consumers be left to fend for themselves?

GE crops in the United States are approved for use by either the Agriculture Department, the EPA, or the FDA, each with its own process.

Bill Freese, science policy analyst at the Center for Food Safety, says the government needs "to improve the regulatory system, which is a rubber stamp designed to enhance public confidence without ensuring safety."

BIO's Lauritsen, meanwhile, "supports the current U.S. regulatory framework," saying "biotech crops go through extensive testing and review."

But Gregory Jaffe, a lawyer who is director of biotechnology projects at the Center for Science in the Public Interest, says "that's misleading. The FDA has a voluntary consultation process, which I think is inadequate." (We've seen what self-regulation has done to financial markets and the waters of the Gulf of Mexico.) The USDA, Jaffe says, does "a fairly good job of ensuring it doesn't have an impact on agricultural interests, but the process to [minimize] environmental impact is inadequate." Jaffe rates the EPA tops at ensuring against food safety risk of the crops it oversees, which includes all that corn.

Bottom line (keeping in mind that I am neither doctor nor scientist):

For the small percentage of the population that's extremely food-sensitive or has severe allergies, it's probably best to avoid GE foods when possible. That means buying organic anything containing corn, soy, or canola (check your labels -- you'll be surprised to find how many food products this includes).

If you care about family farms, personal liberties, or the environment, you should also buy organic -- organic certification means no GE -- wherever practical. Monsanto has used some rough tactics on small farmers that don't toe its company line, and the organic farmers threatened by GE varieties blowing into their fields, or being carried there by birds, tend not to be part of Big Ag. They also support crop diversity and petrochemical-free farming by planting varieties farmers have been using for centuries (and not patented by giant corporations), and by keeping chemical formulations and harmful nitrogen-based fertilizers out of the groundwater and agricultural runoff.

No matter who you are, you should support legitimate scientific review of new biotech crops coming to market; all three regulating agencies have periods of public comment before they OK a new GE crop, and Congress has the authority to change the way GMOs are OK'd by the government.

Finally, if you want to keep your head from spinning, make this the last article you read about genetically engineered foods for awhile.