In the UK, political debate over stem cells continues to focus on whether scientists should be allowed to create hybrid humananimal embryos. This futuristic research may eventually lead to rewarding discoveries about incur-able diseases - and emotive arguments by some religious groups trying to ban it should be resisted. At the same time, some scientists and patient advocates have been unable to resist hyping hybrid embryo research, by implying that it could produce cures in the near future. Sir Martin Evans, the stem cell pioneer and Nobel prizewinner, acknowledged that this week. In the US, meanwhile, the Food and Drug Administration is preparing for the much more immediate business of actually regulating the world's first clinical trials of pro-ducts based on human embryonic stem cells. The FDA held two days of hearings this week to draw up guidelines for assessing the risks and benefits of stem cells in the clinic. Later this year, the agency expects to receive applications to test such treatments on patients; the pioneer is likely to be Geron, a Californian company aiming to restore limb movement in people paralysed by spinal injury. As the FDA hearings demonstrate, the US has moved ahead of the rest of the world in stem cell research, as it has in almost every area of bioscience that really matters. The furore over President George W. Bush's ban on federal funding of embryonic stem cell research gave some people a false impression that the US risked losing its lead in the field to Europe or Asia. While the ban has indeed caused delay and inconvenience to American stem cell scientists, the overall strength of biomedical research in the country, harnessed to the availability of private and state funds, has kept the US at the front of the field. With all three remaining presidential candidates having come out in favour of embryonic stem cell research, that lead can only increase. And demonstrable success of any stem cell product in clinical trials would catalyse private sector investment in the field. For patients with incurable diseases that might be helped by stem cell therapy, a nationalistic view is of course irrelevant; they want cures wherever they come from. Scientists and political leaders elsewhere in the world should take advantage of any expansion of the US stem cell enterprise to build up their own activity - collaborating where possible with American institutions. US leadership of the field leaves huge scope for researchers elsewhere to take part in what still promises to be one of the great biological endeavours of the century. For Britain, hybrid embryo research is likely to be a niche worth exploiting - so long as everyone realises that its fruits lie in the more distant future. Copyright The Financial Times Limited 2008