A much-anticipated review by the British government of genetically modified (GM) crops has found that they are safe to consume but pose a serious threat to the environment. The 300-page report, produced by a panel of 24 scientists and policy advisors, is by far the most exhaustive study of GM crops to date. To the relief of GM advocates, it found that transgenic food products do not currently pose a significant threat to human health. However, the report raised many environmental concerns, such as the likelihood that GM crops will contaminate organic crops. The most alarming environmental problem, according to the report, is the threat posed to wildlife by the ultra-powerful weed-killers that GM crops are bred to tolerate. Widespread use of GM crops could lead to more use of such herbicides, which could wipe out plants and insects critical to the habitat and diet of farmland birds and other wildlife.