Genetic engineering is a technique used to alter or move genetic material from living cells. A genetically modified organism (GMO) is any organism whose genetic material has been altered using genetic engineering. The first GMO was a mouse created in 1973 by transferring antibiotic resistance genes into its genome. Since then, scientists have genetically modified many other organisms like plants, animals and microbes by inserting genes from different species. While GMOs aim to improve traits like disease resistance and yield, some argue they may cause unintended health or environmental risks.