Genetic engineering is the use of molecular techniques to transfer genes from one organism to another, with the transfer usually occurring across species. This process allows scientists to create new crop varieties with novel combinations of traits. The resulting plants may confer enormous benefits or risks on both humanity and the environment at large. Worldwide, almost 70 million acres of farmland were sown with genetically engineered crops in 1998, and the acreage devoted to these "high-tech" crop varieties is continuing to expand.