 The controversy is propelled by a significant public opposition supported by a minority of professionals, which include researchers, dental and medical professionals, alternative medical practitioners, health food enthusiasts, a few religious groups (mostly Christian Scientists in the U.S.), and occasionally consumer groups and environmentalists.Organized political opposition has come from libertarians, the John Birch Society, and from groups like the Green parties in the UK and New Zealand.Proponents and opponents have been both criticized for overstating the benefits or overstating the risks, and understating the other, respectively.