The ethical and scientific debates about the merits and hazards of human ESC research remain thorny, and many scientists agree that other kinds of stem cells—namely, adult stem cells and induced pluripotent stem cells—cannot replace the embryonic kind. Neither alternatives wholly bypass some of the key ethical issues or have been shown to be as biologically flexible as hESCs. The legal arguments currently center in part on just where the research itself starts and ends. In the August 23 decision to impose the injunction, Lamberth explained that "the question before the court is whether ESC research is research in which a human embryo is destroyed," he wrote in his opinion. "The court concludes that it is."
But as human ESC research supporters note, federal funds are not used to derive the stem cells, a process that destroys the embryo. Rather, they are used only to maintain the cell lines and perform further experiments. Hynes explains that although some unneeded embryos from fertility services end up adopted by new parents, most fertilized eggs from in vitro services are left sitting in freezers.
The government argued in a September 8 court document that a line of inquiry "does not mean that each research project includes the projects and actions that preceded it—including projects that were performed by different scientists." And the hESCs currently being used in research, the government has argued, are from lines that had been derived previously, through projects funded by other entities.
Lamberth's interpretation leaves Melton wondering, somewhat facetiously, if embryonic stem cell research led to the discovery of a gene, "does that mean that no one could ever think about the gene [or] write a paper about it?"
The legal case has also opened questions about the function of peer review and intensity of competition for federal grant dollars. The two scientists who brought the case forward work on adult stem cells and have asserted that they face unfair competition for limited government funds if the NIH continues to increase its funding of hESC research. As supporters of human ESC research have pointed out, however, embryonic stem cell research has received about 25 percent ($131 million) of the money the government awards among the three types of stem cell research for the current fiscal year. The two plaintiffs, Theresa Deisher and James Sherley, had until late Tuesday to file a response to the temporary stay, and the government will have until September 20 to reply.
Federal dollars are not the only funds that back stem cell research. Some states, institutions and private companies have put money toward the work, but the NIH is a substantial contributor—as well as a barometer for the industry. Investors "look to other signs whether this is technology worth investing in," Werner says. "If they see that it is going to be prohibited by the courts or shut down, this provides a disincentive." He asserts that, "Long term, it's not tenable if the NIH isn't involved."
The NIH issued a statement on Friday saying, "We are pleased with the court's interim ruling." But not everyone is confident that the temporary stay instituted by the appeals court will last.
"While I am relieved that the injunction has been stayed, I worry that the future of human ES cell research remains at risk," comments George Daley, an associate professor of pediatrics at Children's Hospital Boston who works with human ESCs. "We need a clear statement from the Congress."
But coming into a contentious election cycle with many other major priorities on the national agenda, pushing through new legislation on embryonic stem cell funding might be tricky. "Right before elections Congress often gets kind of partisan anyway," Werner says. "So that's not an environment typically conducive to compromise and working things out." Although many polls have shown that Americans favor continued research using human ESCs to look for cures for diseases such as diabetes and Parkinson's, many conservative groups advocate against any use of the cell lines.
For some researchers, the question of continuing ESC research is in itself an ethical imperative. "I think it's morally offensive to prevent those embryos from being used and throw them down the drain," Hynes says. "The people who are most damaged by this down the road will be the patients and their families," he says.
A congressional hearing on the issue is scheduled for September 16.