A powerful new technique for generating supercharged genetically modified organisms that can spread rapidly in the wild has caused alarm among scientists. The development of so-called gene drive technology promises to revolutionize medicine and agriculture. However, scientists at the forefront of the development believe ... gene-drive technology poses a serious threat to the environment and human health if accidentally or deliberately released from a laboratory without adequate safeguards. Last week the US National Academy of Sciences initiated a wide-ranging review of gene-drive technology in non-human organisms and in this weeks journal Science a group of 27 leading geneticists call on the scientific community to be open and transparent about both the risks and benefits of gene drives. Researchers have likened gene-drive technology to a nuclear chain reaction because it allows GM genes to be amplified within a breeding population of insects or other animals without any further intervention once the trait has been initially introduced. This is the case even if the trait is non-beneficial to the organism. Laboratory experiments on fruit flies have shown that a modified gene introduced into one individual fly can take just a few generations to infect practically every other fly in the breeding population, in defiance of the normal rules of genetics which dictate a far slower spread.