The national debate over human embryonic stem cell research -- one that has pitted religious objections against the promise of major scientific and therapeutic advances -- has been reawakened by a dramatic advance that could have been made in the United States, but wasn't. That's because on Aug. 9, 2001, President Bush announced that only stem cell lines obtained before that date could be used in research supported by federal funds. This has virtually halted a vital area of medical science here because development of an equivalent level of private support will require many years. And that's why the new excitement comes from South Korea, not from this country. The stakes are high. Stem cells, which can be obtained from human embryos otherwise discarded at fertility clinics in the course of assisted reproduction, are capable of forming all of the tissues of the adult human body under the right circumstances. They are of enormous potential advantage in the treatment of Parkinson's disease, spinal cord injuries, Alzheimer's disease and diabetes. So what's wrong with the dozen or so old cell lines we have? The problem is that most of the approved lines are unavailable, or otherwise guarded by murky intellectual property claims. The way they were made and their limited genetic diversity limit their therapeutic utility. More important, new technology has taken us beyond their capacity. The recent experiments performed in South Korea have produced a robust line of stem cells, derived from blastocysts that were produced by activating eggs taken from female volunteers with nuclei taken from body cells of the donor. This process, called somatic cell nuclear transfer, is viewed by some as akin to cloning people, which no one in the scientific community favors. Instead, it provides a way to explore the early processes of human development and develop novel ways of understanding the basis for genetic predisposition to late-onset diseases. It is essential research, and it is needed here. Yet if the congressional opponents of stem cell research have their way, a bill already passed by the House and now being considered in the Senate would make such work a crime. In South Korea, cloning for reproductive purposes is against the law. But this work, plainly aimed at scientific and therapeutic purposes, was encouraged and supported by the government. If we decide to discourage or even criminalize such experiments here, they will be done elsewhere -- and the benefits will be reaped by others. One option in this country is to approach a solution at the state level. Some states have passed laws that make cloning people illegal but allow cloning stem cells -- an important distinction that Congress has so far been unwilling to make. And some states have developed the means for raising funds to support the kind of research that now cannot be done with federal funds. A forthcoming ballot initiative in California would appropriate $350 million each year to support stem cell research. It would create a California Stem Cell Research and Cures Fund, to be distributed by an Institute for Regenerative Medicine, overseen by an independent citizens committee selected from academic and research institutions. The funding plan rests on the authorization of a $3 billion general obligation bond issue. For the first five years, a positive tax revenue stream generated by the initial expenditures will make it possible not to burden the state's general fund while it recovers from its present economic stress. The California experiment is an interesting one. As Californians and scientists, we hope for its success. But we also hope that it will be a signal for other citizens -- that there are domestic alternatives to a national policy that threatens to drive an important and valuable research activity overseas. A California resolution would be nice for us, and for the California economy. But if we can't find a solution that permits stem cell research at the federal level, the result will be costly for our national health.

• DAVID BALTIMORE is president of the California Institute of Technology;
• PAUL BERG is a professor of biochemistry at Stanford University;
• DONALD KENNEDY, former Stanford president, is editor-in-chief of Science magazine; and
• IRV WEISSMAN is a professor of cancer biology at Stanford. They wrote this column for the Mercury News.