Genetically modified crops are agricultural products produced from seeds that have been modified at the genetic level (DNA) to alter the product in a way that benefits the production of that crop. Genetic alterations help provide crops that have increased resistance to insects and drought and generally help increase yields. One concern that many have with these altered crops is that since they are widely accepted foods, they are not tested in a clinical type setting like pharmaceuticals or makeup products are. The concern is not so much with acute exposure, but what long term exposure to these products might do to adversely affect the body. Another concern is over food allergies. Altering genes of foods can cause food allergies to appear in people who are otherwise not allergic to the wild type strain of the food. All of this has lead many to advocate for the complete labelling of genetically modified crops and products made using them so that people can decide what to purchase for themselves.