Of the hopes invested in Barack Obama, few are greater than those of seriously ill people who may be helped by embryonic stem cells. President Bush's ban on most federal funding of research into these cells has hampered efforts to develop their medical potential. President Obama has pledged to lift the ban and to introduce a more liberal regime like Britain's. This will enable the world's premier paymaster of medical research, the US National Institutes of Health, to support stem-cell science as it sees fit.

But as US scientists await injections of cash, their British counterparts have received less welcome news. Only a few months ago the Human Fertilisation and Embryology Act was passed, permitting stem cells from human-animal hybrid embryos to be used in the investigation of many diseases. The first such studies, however, have been refused government funding. This has provoked outrage from two very different constituencies. MPs, patient groups and scientists who campaigned for this research have been angered that experiments they worked hard to facilitate are still being blocked. Ethical opponents of hybrids, meanwhile, have cited the funding decision as proof that this science was all hype and should never have been approved.

Both sides of the argument are founded on the same misconception about government's role in medical research, ie, to assume that questions about whether experiments should be permitted, and whether they should be funded, are intrinsically linked. Yet the considerations involved are very different. When legislating, governments need to establish the limits of what society is ready to allow scientists to do. This means prohibiting only practices that are either dangerous or morally unacceptable to a large majority. The hybrids debate made it plain that the technology fell at neither hurdle. The Government thus concluded that it should not be banned. It refused, unlike President Bush, to let the moral qualms of a few hold up promising science.

But that decision in no way made hybrid experiments a priority. Yes, they have potential to improve our understanding of disease, but so do other scientific techniques, and the available public funds are limited. Few politicians are well versed in the detail of science and should thus avoid trying to pick winners. They are better off setting up a broad regulatory framework and devolving funding decisions to research councils with specialist expertise.

That is what has happened in the case of hybrids. The research councils, which receive five times as many grant applications as they are able to approve, have been forced to make tough decisions based on the competing claims of many worthwhile projects. That the experiments have lost out does not mean that they are valueless. And that the Government considered them permissible does not mean that they deserved a cheque. They had to stand and fall on their merits.

This is as it should be. Governments should generally avoid being either too prescriptive or too proscriptive in their management of science, leaving those who really understand it to set the direction of travel. That, by and large, is how stem-cell research is proceeding in the UK. President Obama's reforms should soon allow the US to follow suit.