Genetically modified foods have been altered to develop potentially desirable qualities, such as the ability to grow year-round, be pest-resistant or have enhanced taste or added nutritional value.

Genetically modified foods are produced using gene splicing (recombining the DNA of two different organisms). This involves taking a gene (or genes) from one organism and placing it in another. Gene splicing is an improvement over the more time-consuming traditional genetic modification techniques, such as plant grafting (attaching a portion of one plant to another) and hybridization (sometimes called cross-breeding), in which two different plants are bred to produce offspring with qualities of both parent plants. These methods also resulted in the transmission of undesirable traits as well as desirable traits.

The first genetically modified foods focused on making plants easier and cheaper to produce. This resulted in plants that were more pest- and disease-resistant and able to withstand the use of herbicides. Later, genetically modified foods focused on traits beneficial to the consumer, such as enhanced nutritional value and improved appearance and taste. More recent genetic modification has focused on the potential pharmaceutical and environmental uses of genetically modified plants. Genetically modified foods are relatively new, first becoming available in the 1990s. To date, the U.S. Food and Drug Administration (FDA) has approved over 50 genetically modified foods.

Genetically modified foods may provide potential benefits such as reduced production costs, improved availability and the use of fewer chemicals (e.g., pesticides) during production. However, a number of concerns have also been raised regarding genetically modified foods, including the potential for introduced allergens, adverse long-term health effects as well as environmental and ethical concerns.

Genetically modified foods are regulated by the FDA, U.S. Department of Agriculture (USDA) and Environmental Protection Agency (EPA). The FDA is responsible for ensuring genetically modified foods are safe for human consumption. The USDA is responsible for ensuring genetically modified plants are safe to grow and do not harm other plants or the environment. The EPA is responsible for ensuring genetically modified foods are safe for humans, animals and the environment. While these agencies act independently, they have a close working relationship since many products come under the review of all three.

The FDA does not require genetically modified foods be identified on product labels, as long as they are “substantially equivalent” to their conventional counterparts. This means they should have the same nutritional value, allergens, and nearly the same composition and characteristics of their counterparts. However, in many other parts of the world (e.g., the European Union, Japan), all genetically modified foods must identified as such on their labels. Because of this, exports of genetically modified foods from the United States to these countries have been banned.