Editor's note: The terms GE (genetic engineering) and GMO (genetically modified organism) are often used interchangeably, but their meanings are different. GMOs, which are produced when plant breeders select genetic traits that may also occur naturally, have been around for centuries. Common examples are seedless watermelons and modern broccoli. The subject of much recent debate are GE foods, which have only been around in recent decades and are produced by transferring genes between organisms. The resulting GE organisms—either plant- or in the case of GE salmon, animal-based—would not otherwise occur in nature. This article is about GE foods.