What hope does embryonic stem cell research hold for people who suffer from debilitating diseases? What place does the regard for human life play in scientific research? After Ron Reagan's speech to the Democratic convention, where he challenged Bush administration policy on embryonic stem cell research, we asked two scholars on either side of the debate to discuss the latest scientific and ethical issues.

Ronald M. Green, chair of the department of religion at Dartmouth College, serves on the Ethics Advisory Board of Advanced Cell Technology, a biotechnology company.

Nigel Cameron is research professor of bioethics at Chicago-Kent College of Law and president of the Institute on Biotechnology and the Human Future.

Anyone who concluded from Ron Reagan's remarks that stem cells promise an imminent cure for Alzheimer's disease is mistaken. Stem cell transplant therapies for neurological diseases are still years away, and then most probably for conditions like Parkinson's disease. The damage caused by the buildup of diseased cells and plaques in Alzheimer's disease is so extensive that it is hard to see how any transplant could help.

Nevertheless, Ron Reagan is right for several reasons to stress the importance of stem cell research and to appeal for a change in current regulations.

First, a journey of many miles requires a first step. Research begun now with adequate federal support will undoubtedly lead to breakthroughs, some of them currently unanticipated. I fail to understand the logic of those who oppose research because the benefits are not presently obvious. Research is always a step into the unknown. You would not do research if you knew the answers.

Second, even though it is unlikely that stem cells will soon lead to therapeutic transplants, these technologies (including the use of biomedical cloning) can help us produce a series of model cell lines exhibiting the Alzheimer pathology. This will allow us to study the disease progression in the laboratory and better understand what goes wrong with neuronal functioning where the disease is present.

Such research could get underway in the near future if federally funded researchers had access to a much larger population of stem cells. It will very clearly not progress if federally funded research is confined to the 20 lines approved for use by the Bush administration.

Finally, in evaluating Ron Reagan's remarks, let's not forget that the opposition to this research is formidable. The opponents have managed to outlaw research using human embryos in this country for over 20 years. Sadly, the majority of Americans, who do not share the extremist views that drive this opposition, are largely unaware of this politics of obsruction. It is the nature of our political system that people are only stirred when they are awakened by alternate visions and dreams.

That's what Ron Reagan tried to do, and he should be applauded for his courage.

In his enthusiastic seconding of Reagan's call (which has helped land the hapless John Kerry with a policy that would not only permit the mass cloning of human embryos, but fund it) Ron Green perpetuates some deep misunderstandings that in someone less informed and sophisticated one might have been tempted to forgive.

He fails to grasp, or at least uncover, the thorough-going disingenuousness of the Reagan speech, which offers a full-blown call for human cloning while never coming close to using the word. The argument is not for a few extra embryos or a few extra dollars. It is for industrial-scale Dolly-style human manufacture. If "therapeutic cloning" is ever to be possible it will require hundreds of millions of human eggs, and the destruction of human embryos on a truly vast scale.

Moreover, Ron Green perpetuates some grave misunderstandings of the situation. For example, he claims that opponents of embryo research "have managed to outlaw research using human embryos in this country for over 20 years.

" One must suppose that he meant to say was that there has been no federal funding for such research. There are in fact no restrictions in federal law on embryo research.