Genetically Modified Organisms (GMO) are plants or animals that have been genetically engineered. Many industries support the development and use of GMOs while many consumers and organizations question their safety and have called for adequate and independent testing of GMO products. It is legal for farmers in the U.S. and some other countries, like Argentina, to produce and sell certain GMOs for human and animal consumption, but in other places like Europe and Japan, they are banned until further testing can be done to prove they are safe. In the United States, labeling of GMO foods is not required, meaning consumers have no way of knowing whether they are consuming products with GMO contents.