Worse, according to a row crop farmer I know, one can safely say that almost all conventional corn and soybeans contain some level of GMO contamination due to cross-pollination (in the case of corn) plus both intentional and accidental commingling during storage, transportation and processing.

Consequently, if you're eating anything that contains corn or soybeans in any form, you're almost certainly eating genetically-modified food--unless the corn or soybeans are certified organic. This includes easily-identifiable foods like sweet corn or tofu or corn tortilla chips or soymilk or corn oil but also a huge number of processed foods containing corn or soybean oil (or both) and/or high-fructose corn syrup (which is ubiquitous in processed foods because it's a cheaper sweetener than cane sugar). If you're eating at a restaurant, there's a good chance that any oil used to prepare the food--and lots of oil is used to prepare the food in most American restaurants--was genetically-modified soybean oil, and it was probably hydrogenated to boot. Cottonseed and canola oils from GMO crops are also found in some foods.

But does it matter? After all, there are no news stories of people dropping dead or even becoming terribly sick after eating GMO food, right? True, but that doesn't mean there are no destructive health effects. First of all, the government doesn't require companies to label GMO foods and has no comprehensive program to detect and report harm caused by GMO foods; even if people are dying or getting acutely sick from eating GMO foods, we wouldn't necessarily know GMO foods were the cause because few people know they're eating GMO foods and the government isn't monitoring for harmful health effects, anyway.

Sudden death and acute illness aren't the only issues, either. Many harmful substances only cause detectable damage over time, due to repeated exposures. If GMO foods are causing or contributing to hormonal problems, cancers, diabetes, infertility, organ damage, or any other health condition, we won't know for years, if ever, because, again, the government isn't carefully watching for problems.

Even if you manage to avoid directly eating conventional corn and soybeans and all the ingredients derived from them, you're only once removed from eating GMO food if you're eating animal foods--meat, dairy products, and eggs--that aren't certified organic. Corn and soybeans are the primary ingredients in the feed that makes the industrial animal factories possible. We are not only what we eat, but what we eat eats.

And, at the same time GMO corn and soybeans have come to dominate the market, ongoing research into how genes actually work has been in the process of undercutting the assumptions that underlie GMO biotechnology. A recent New York Times article gives more details, but the short version is this: While the biotech industry treats genes as independent entities that can be neatly plucked from one organism and inserted into another to produce some desirable--that is, profitable--trait, in actuality genes appear to operate in complex networks whose interactions are far from fully understood. Given this, there are inevitably going to be unpredictable consequences from plucking a gene out of one complex network and forcing it into another it did not evolve as part of. Are the "benefits" of herbicide-tolerance and Bacillus thuringiensis-toxin really worth that risk?

I think it's important to remember that, whenever you buy something, the implicit message you send, whether you want to or not, is "Yes, please, make more just like this." I'm not suggesting anyone be a complete purist--I don't completely avoid eating foods that may well come from GMO sources, particularly when I eat at restaurants--but the great majority of the foods I buy to eat at home are either locally-grown organic or non-local certified organic.

For more info about GMO foods, you can visit the Genetically Engineered Food page of the website of the Center for Food Safety . To tell your Congressional representatives that you want the FDA to require clear labels on GMO foods, go to the site of the Campaign to Label Genetically-Engineered Foods.