When embryonic stem cells prove their medical merits, public support--both social and financial--will probably grow substantially, said National Institutes of Health director Elias A. Zerhouni in a panel discussion held Wednesday in Washington, D.C., by Scientific American. Comparing the state of embryonic stem cell science today to that of organ transplantation during the 1950s and '60s, Zerhouni noted that public consensus in favor of organ transplants only emerged when the "greater good" offered by the treatment had been fully demonstrated.

"This is the people's dollars we're talking about," Zerhouni stated, "and that's where the rubber hits the road." Without public consensus, he explained, consensus in Congress to expand funding for embryonic stem cell science is unlikely. "California is going to test that," he added.

A November 2 California ballot initiative seeking to raise $3 billion for stem cell research in that state loomed large in the panel's discussion of the best way for science and society to proceed with regard to embryonic stem cell research. If passed, California's Proposition 71 might break an essential impasse in the debate over using embryos in research. Proponents say that without adequate funding and materials, U.S. scientists cannot fully explore the potential of embryonic cells. Critics counter that without demonstrated medical potential, the ethical risks of expanding embryo research are too great.

The panel of senators, scientists and ethicists revisited those arguments in Wednesday morning's discussion moderated by Scientific American Editor-in-Chief John Rennie.

Panelist Robert Lanza, of the Massachusetts-based biotech company Advanced Cell Technology (ACT) cited a study he and colleagues published just last week, demonstrating for the first time that embryonic stem cells could be coaxed to become Retinal Pigment Epithelium (RPE) cells. Replacement RPEs could be used to treat eye diseases such as macular degeneration and retinitis pigmentosa, but Lanza said his group's discovery might never have been made had their work been confined to NIH-approved cell lines. Their experiment used both NIH lines and newer cell lines created with private funds, and whereas the new cell lines readily produced RPEs, the NIH lines required tremendous effort to eventually do the same. "Only because we were able to figure out the exact protocols that worked with the new lines, we were able to keep trying until we got the old lines to work," Lanza noted.

Researchers have complained that the so-called presidential embryonic stem cell lines, those created before August 2001--the only ones eligible for federally funded research--are inadequate in number and in quality. With age, some of the approved lines have become difficult to sustain, a few have shown chromosomal abnormalities, and all have spent time growing on a medium containing mouse cells, creating the possibility of contamination by animal viruses.

Zerhouni commended Lanza for characterizing the abilities of new cell lines because such work will help to resolve what is "needed" for research to progress in this relatively new field. California State Senator Deborah Ortiz (D-Sacramento), however, criticized the lack of federal support for resolving unanswered questions about embryonic cells and their potential, saying that the "tide seems to be turning on the federal level toward criminalizing" the research.

A leading proponent of Proposition 71, Ortiz confirmed that the bond-issue initiative is intended to fund all types of stem cell research, but particularly work prohibited by the federal restrictions, such as creation of new embryonic stem cell lines from donated IVF embryos. Ortiz called the $3-billion initiative, which could cost an additional $3 billion to implement, an investment in California's biomedical science infrastructure, adding that she hoped it would lure the best stem cell scientists to her state. (Lanza said later that ACT may indeed open a research facility in California.)

Panelist William B. Hurlbut of Stanford University, a member of the President's Council on Bioethics, pressed Ortiz to acknowledge that the state funds could also be used for creating new embryos with the intent to destroy them for research. In 2002 California passed a law expressly forbidding human reproductive cloning, but not the creation of embryos through somatic cell nuclear transfer (SCNT) to derive stem cells for research and treatments, commonly known as therapeutic cloning. "We can change the words but we would be obfuscating the issue," Hurlbut declared.

Ortiz noted that at least California has a law prohibiting the use of SCNT for reproduction, whereas the federal government does not. Rennie asked the panelists whether the limited federal regulation and funding for embryonic stem cell research effectively cedes difficult policy decisions to the states and private sector. A quarter century ago, Rennie remarked, the emerging field of assisted reproduction was considered ethically "too hot for the federal government to touch" and as a result, the technology developed essentially unmonitored and unregulated.

"It would be much better to have a national and even an international policy," Hurlbut responded. In a report published earlier this year, the President's Council on Bioethics urged increased scrutiny of all reproductive technologies and research involving embryos, including a ban on work with embryos more than 14 days past fertilization. "That 14 days was a number picked out of the sky anyway," Hurlbut asserted, however, "for the moment, we should keep the current policy until we get through the [ethical] debate." Panelist David A. Prentice of the conservative Family Research Council added that "everyone's uncomfortable" with President Bush's compromise policy allowing federal funding for research with embryonic cells, but only those cell lines created before August 2001.

Senator Sam Brownback (R-Kansas), sponsor of a bill (S 245) to ban any use of SCNT, opened the panel's discussion by noting that social debate over the ethical status of embryos has been around since the 1973 Roe versus Wade abortion case. "What is a child, a person or property?" Brownback asked.

Senator Richard Durbin (D-Illinois), sponsor of a competing bill (S. 303) that permits therapeutic cloning while banning reproductive cloning agreed that "in the real world of Washington," the debate over embryo research is inextricably linked with the abortion issue and is thus unlikely to be resolved soon. "You can't discount that this relates to religious, ethical and political issues that have tied us up for decades," he said.