Genetic engineering (GE) is the modification of an organism’s genetic composition by artificial means, often involving the transfer of specific traits, or genes, from one organism into a plant or animal of an entirely different species. When gene transfer occurs, the resulting organism is called transgenic or a GMO (genetically modified organism). Critics of genetic engineering believe that GE foods must be proven safe before they are sold to the public. Specific concerns over genetic engineering include:
Antibiotic resistance. Almost all GE foods contain antibiotic resistance marker genes that help producers know whether the new genetic material was transferred to the host plant or animal. GE food could make disease-causing bacteria even more resistant to antibiotics, which could increase the spread of disease throughout the world.
Allergic reactions. There are two concerns regarding allergic reactions. The first is with known allergens. For example, if genes from nuts are inserted into other foods, it could cause severe reactions in people with nut allergies. Therefore, there is concern that people with known allergies will not be aware that the genetically engineered food they are eating contains substances to which they are allergic. The second concern is that new allergies might be created, since new combinations of genes and traits have the potential to cause allergic reactions that have never existed before.
Loss of nutrition. Genetic engineering may change the nutritional value of food.
Foods that have been approved for GMO by the FDA but not necessarily in the grocery store yet are starred (*): Alfalfa, Cherry Tomato*, Corn, Flax*, Papaya, Potato*, Rice*, Soybean, Squash, Sugar beet, Tomato*
More info: http://www.sustainabletable.org/264/genetic-engineering