Two reports were published in December concerning the effects of transgenic crops on both the environment and food supply. Although one of them finds that GM foods have shown no adverse human health effects, both calls for further study. The first report, sponsored by the American Association for the Advancement of Science (Washington, DC), analyzed 35 peer-reviewed studies that examined potential emergence of “superweeds”, unintended consequences of the spread of viral diseases, and possible harm to nontarget species, but determined the potential environmental detriments of GM crops to be inconclusive (Science 290, 2088–2093, 2000). Meanwhile, a review by the American Medical Association (AMA; Chicago, IL) noted that 40 transgenic crop varieties have been cleared by the US government, and that crops and food produced using recombinant DNA techniques have been available for 10 years without any long-term human health effects. The AMA recommends science-based regulation of GM crops and continued research into potential environmental risks, but deems the labeling of GM foods unnecessary, because “these foods are substantially equivalent to their conventional counterparts.”