Correction Appended

(Page 2 of 2)

If farmers in developing countries accept this crop and if the millions of people who suffer from nutrient deficiencies will eat it, golden rice could prevent widespread anemia and blindness in half a million children a year and the deaths of one million to two million children who succumb each year to the consequences of vitamin A deficiency.

Future possibilities include peanuts or shrimp lacking proteins that can cause life-threatening food allergies, fruits and vegetables with longer shelf lives, foods with fewer toxicants and antinutrients, meat and dairy products and oils with heart-healthier fats and foods that deliver vaccines.

Real and Potential Risks

G.M. foods and crops arrived without adequate mechanisms in place to regulate them. Three agencies are responsible for monitoring their safety for consumers, farmers and the environment: the Food and Drug Administration, the Department of Agriculture and the Environmental Protection Agency. But the drug agency says its law does not allow it to require premarket testing of G.M. foods unless they contain a new substance that is not ''generally recognized as safe.''

For most products, safety tests are done voluntarily by producers. The recent recall of taco shells containing G.M. corn that had not been approved for human consumption was done voluntarily by the producer. The agency is now formulating new guidelines to test G.M. products and to label foods as ''G.M.-free'' but says it lacks a legal basis to require labeling of G.M. foods.

''In the current environment, such a label would be almost a kiss of death on a product,'' said Dr. Michael Jacobson, director of the Center for Science in the Public Interest, a nonprofit consumer group. ''But it may be that the public is simply not going to have confidence in transgenic ingredients if their presence is kept secret.''

The introduction of possible food allergens through genetic engineering is a major concern. If the most common sources of food allergens -- peanuts, shellfish, celery, nuts, milk or eggs -- had to pass through an approval process today, they would never make it to market.

But consumers could be taken unaware if an otherwise safe food was genetically endowed with an allergen, as almost happened with an allergenic protein from Brazil nuts. Even if known allergenic proteins are avoided in G.M. foods, it is hard to predict allergenicity of new proteins.

A potentially serious environmental risk involves the ''escape'' of G.M. genes from crops into the environment, where they may harm innocent organisms or contaminate crops that are meant to be G.M.-free.

Dr. Jacobson concluded, ''Now is the time, while agricultural biotechnology is still young, for Congress and regulatory agencies to create the framework that will maximize the safe use of these products, bolster public confidence in them and allow all of humankind to benefit from their enormous potential.'' Two Congressional bills now under discussion can do much to assure safer use of agricultural biotechnology, he said.

Chart: ''Genetically Engineering Crops'' Agricultural scientists can take the genes responsible for a desired trait from any organism and introduce it to a given crop. ONE METHOD Researchers place the desired genes into a bacterium that naturally alters a plant's DNA, then infect the plant. The bacterium inserts the new genetic codes into the plant's DNA. The cells are then grown to maturity, producing future generations with the desired characteristic.