They attempt to narrow gap between scientists and critics, who say the study is immoral and illegal.
A new set of rules for medical experiments is rekindling an impassioned debate that touches on scientific ethics and the politics of abortion.
The central question: Should the federal government pay for research that destroys human embryos?
This week, the National Institutes of Health (NIH) issued guidelines for scientists who study unique embryonic cells that, for a brief period after conception, can become almost any type of tissue in the human body.
Researchers say these cells have enormous therapeutic potential, perhaps serving as repair kits for diseased or damaged tissues. Yet the government has refused to fund study of human versions of these cells, called embryonic stem cells. In 1996 Congress banned the use of tax dollars for research in which human "embryos are destroyed, discarded, or knowingly subjected to risk of injury or death."
Yet the NIH has moved ahead despite the ban. It's an effort to give researchers access to federal money while trying to address ethical issues the research has raised among some groups.
Among the new rules:
*Human embryonic stem cells can only be taken from embryos that are going to be discarded anyway. For example, embryos that remain after women complete or end treatment at in-vitro fertilization clinics.
*The NIH will refuse to fund research on embryonic stem cells if the donor was coerced or paid to provide embryos solely for research purposes.
*Companies supplying stem cells must get informed consent from women whose unused embryos are being sought.
By opening the research to federal funds, developments in the field are likely to accelerate, says Paul Berg, a Stanford University biologist and Nobel Prize winner. The guidelines "will enable research to advance without violating the ethical and moral sensibilities of the American people," he adds.
Critics of the new rules come from both sides. Anti-abortion members of Congress and groups such as the National Right to Life Committee argue that the new rules are immoral and illegal, given the congressional ban.