What's Left to Eat?

Genetic Engineering: Miracle or Monster?

Scientists can pluck a genetic sequence (one part of a gene) from one species and insert in into the DNA of another species. Will genetic engineering bring abundant harvests and earth-friendly farms? Or will it raise a crop of problems?

Governments, universities, and nonprofit groups led the research effort that yielded the Green Revolution of the 1960s and '70s. Things are different with GE food. Large corporations fund and direct most bioengineering research. This creates quite a paradox.

On the one hand, companies eagerly apply for patents to protect their discoveries. No one else can produce the same GE plant or seed. Farmers who want it must then pay whatever the company charges.

Farmers who don't want GE crops sometimes must pay for them, too. When GE seeds got into a Canadian farmer's canola crop, the company that produced the seeds sued the farmer. They claimed he was violating their patent. And yes, they won.

On the other hand, producers of GE food vigorously oppose labels on their products. Labels, they argue, would unfairly suggest that GE foods are drastically different from others. Genetic engineering, proponents say, is simply another kind of crop improvement and humans have created genetically altered plants for millennia.

If GE foods are different enough to warrant patents, critics ask, aren't they different enough to be labeled? Critics also argue in favor of labels to show that GE foods are "unnatural."


Imagine this scenario. You are about to eat a hot, tasty slice of pizza. It's oozing with tomato sauce, mozzarella cheese—and fish. Yes, fish. Not anchovy, but arctic flounder. Where did that come from?

As their name suggests, arctic flounder live in frigid water. The fish have a gene that helps them resist the cold. That gene sounds perfect for tomatoes, which are vulnerable to frosts. That's where genetic engineering (GE) enters the picture. It's the transfer of genes from one species to another. Adding the flounder gene to a tomato plant could create frost-resistant tomatoes. But controversy and negative publicity caused the manufacturer to take such tomatoes off the market.

Genetically modified tomatoes. Photo by Jack Dykinga, USDA Agricultural Research Service
A scientist examines genetically modified tomatoes.
Photo by Jack Dykinga, USDA Agricultural Research Service

Those rugged tomatoes are just one example of genetically engineered food. GE foods, as they're commonly called, have become increasingly common. (GE food is also known as bioengineered or transgenic food.) Sixty percent of the processed foods in an average American supermarket now contain genetically engineered ingredients. This is largely because in the U.S. most of the soy crop—which makes its way into many processed foods—has been genetically modified.

Is genetic engineering new? People have been altering plants and animals since the beginning of agriculture more than 10,000 years ago. What's new about genetic engineering is the ability to transfer specific, desirable traits among different species and strains of plants and animals.

Scientists have a term to describe all human-designed changes in a plant or animal, whether they be through traditional breeding or genetic engineering. This term is genetic modification (GM). It can get very confusing because many people and news account use genetically modified (GM) and genetically engineered (GE) interchangeably.

GE food now grows on all six inhabited continents, though the U.S., Canada, China, and Argentina produce the bulk of it. During 2001 alone, the global production of bioengineered crops increased by 20 percent.


Anyone who's read or seen Frankenstein knows that messing with nature can have bizarre and dangerous consequences. So why do it? Advocates of genetic engineering say that it can benefit humankind in a variety of ways, including:

Scientists could create plants with stronger natural defenses against microbial and insect pests, reducing farmers' dependence on expensive and dangerous pesticides. In the case of cotton, reductions in insecticide use is already documented.

  • Rice. Photo by Keith Weller, USDA
    Photo by Keith Weller, USDA
    Genetic engineering could lead to larger and more nutritious crops of key foods, such as rice, cassava, maize, wheat, yams, sorghum, and sweet potatoes.
  • And increased crop yields are associated with insect-resistant GE plants.
  • Added genes could equip plants to survive in poor soil, arguing that such crops could require less irrigation. Land currently afflicted by excessive salinity or alkalinity could become productive.
  • GE produce could last longer before rotting. This could be a boon to some parts of the developing world, where poor roads may mean a long trip from field to market.
  • Crucial vitamins and minerals could be added to wheat and other crops, as is already done with addition of vitamin A to rice in some parts of the world.
  • Production of vaccines, pharmaceuticals, and other compounds in plants could be beneficial. Such biopharming could benefit poor, rural economies, and be a cleaner and more sustainable way of manufacturing such products.

Advocates also point out that genetic engineering is not irreversible, and that the history of traditional plant breeding shows that problems that may occur can be corrected.

You can find more arguments in favor of GE food at the Food and Agriculture Organization, a part of the United Nations.


Wait a minute, argue opponents of bioengineering. Allowing the spread of GE foods, they warn, is like diving into a pond without knowing its depth. "Frankenfoods" or GE foods haven't been around long enough for anyone to know their long-term effects. Experts paint disturbing scenarios:

  • Genetic modification could mean more allergy attacks. Wheat, legumes, milk, eggs, shellfish, and some varieties of nuts contain allergens. They can cause allergic reactions that include hives and breathing difficulties. Severe reactions can be fatal. Not surprisingly, people generally avoid foods to which they are allergic. But GE techniques could make doing so impossible, either by moving known food allergens between species or by creating new allergenic proteins that may be difficult to identify. Suppose carrot growers added a peanut gene to their seeds. Without labels, how would someone allergic to peanuts know not to eat the carrots?


Peanuts. Photo by Ken Hammond, USDA
Photo by Ken Hammond, USDA


  • GE foods could prove difficult to regulate. Take the case of StarLink, a bioengineered corn variety. Back in the 1990s, the U.S. approved StarLink as an ingredient in animal feed, but not for human consumption. But StarLink began showing up in taco shells, corn chips, and other supermarket items. The scare prompted widespread recalls that cost half a billion dollars.


Corn. Photo by Charles Herron, USDA
Keeping track of corn is harder than it sounds. Photo by Charles Herron, USDA


  • As pollen spreads, genes do too. That means genes from bioengineered plants could wind up in non GE-plants. Those plants could then become superweeds that compete with GM crops. To date, all efforts at bioconfinement—preventing the spread of GE genes—have had only limited success. And what if pharmaceutical or vaccine genes spread into corn and other such crops?
  • Genetic engineering has created plants, especially cotton and corn varieties, that contain built-in pesticides called Bt proteins. Widespread planting of such varieties will inevitably spark the evolution of pests that resist these pesticides and therefore could chomp GE crops with ease. What is a matter of debate is how quickly this would occur. Regulations allow organic farmers to use Bt as a natural pesticide so Bt-resistance is a threat to them as well. All of this could increase, rather than decrease, farmers' dependence on pesticides.
  • In reality, much of the GE food on the market today is designed to be pesticide-resistant, which actually increases farmers' reliance on chemical pesticides.
  • GE plants may give large corporations too much control over farmers. Bioengineered "suicide" or "terminator" plants have sterile seeds so farmers cannot "save" them for the next year's planting. Controversy forced the corporations to pull such plants off the market, but farmers who purchase GE seeds must still sign contracts promising not to "save" seeds. Farmers must therefore buy new seeds each year—a huge expense, and all but impossible for farmers in developing countries. More than a billion farmers—who produce a fifth of the world's food—get seeds the old-fashioned way: by collecting them from each year's crop. But they can't do it with sterile seeds.

Finally, opponents of GE food argue that the vast majority of GE crops are designed to increase profits rather than improve world food production or provide more food to the world's hungry people. Statistics show that very few acres are planted in developing countries—the very places which need food the most.

You can find more arguments against GM food at the Food and Agriculture Organization, a part of the United Nations.


Insects, birds, wind, and water spread seeds and pollen. By and large, that's great. But what happens when GE seeds land where they're not wanted? The result can be genetic pollution. Not long ago, researchers tested 20 different "GE-free" products. Eleven contained tiny amounts of GE ingredients, and five were loaded with them. Such contamination can also occur when seeds are mixed during storage or shipment.

Genetic pollution can mean big trouble for farmers. In Iowa, for example, seeds from GE corn sprouted in nearby fields. The invasion has destroyed some farmers' ability to market their corn as organic since U.S. organic food standards prohibit genetic engineering.

In 2002, parts of southern Africa offered a stark example of how even the fear of genetic pollution can affect people. Famine struck, and the U.S. offered to donate corn. Some nations wouldn't take it because it was GE. Leaders feared that their countries would lose the ability to sell produce to Europe, where shoppers are highly skeptical of GE produce and where many countries require it to be labeled. Temporary suffering and even death of some of their people from famine, the leaders thought, was better than losing money in trade with Europe and risking permanent poverty.


We don't have all the answers about genetic engineering. Even more difficult, we probably don't even know all the questions. That leads some people to recommend that we follow the precautionary principle. It's an approach in which governments, industries, and individuals utilize good science as the foundation for wise decisions, and that when there is not enough data and when the consequences are likely to be serious and irreversible, the wisest action can be to proceed slowly and carefully, and err on the side of caution.

You can be a virtual bioengineer at PBS's Engineer a Crop page.


health_iconShould GE foods be labeled?

science_iconWhat does "natural" mean?



What happens when we mess around in nature's lab? back_eatnext_eat What are the net results of eating fish?

Additional information