Sir

Your Editorial ”Disease insights from stem cells“ (Nature 422, 787; 2003) gives the impression that most US scientists support human embryonic stem-cell research. Not everybody would agree; I would like to state a less reported view.

The suggestion made by some that cloned human embryos will provide otherwise unobtainable cells for disease research misleads the public. There are available countless cell lines derived from a wide variety of normal and diseased human tissues. A greater concern is the practice of understating the scientific challenges of using human embryos to produce mature adult tissues in vitro or in vivo. For embryonic stem cells to make adult tissues, they must first be converted into adult stem cells. All the fuss over embryonic stem cells has damaged public enthusiasm for any type of stem-cell research.

The US Congress should target as much as $200 million of funding for research over the next five years to realize the promise of stem cells for human therapies. This would provide enough money for several projects at each of the 18 National Institutes of Health (NIH). This cost is a small fraction — less than 1% — of the present NIH budget (more than $27 billion). Both adult stem-cell research and non-human embryonic stem-cell research should be supported. Non-human research might one day yield methods of reprogramming human cells to early developmental states without creating or destroying human embryos.

Congress should motivate stem-cell scientists to do what is in the best interest of the public. This is a necessary tension to ensure the long-term quality of the publicly funded research enterprise. As for human therapeutic cloning, the US public has been waiting a long time for leadership that is both moral and based on good science. In the long run, the best interest of the public will also be the best interest of scientists.