At first glance, the nation's emotional debate over stem-cell research seems a mere rerun of the unending dispute over abortion. Both involve the questions about protecting the development of human life, after all.

But there are important moral and religious distinctions between the two issues, and some groups that oppose abortion are not offended by stem-cell experiments — even though they necessarily destroy human embryos.

Yale University ethicist Gene Outka frames the issue partly as one of urgency — saying that abortion involves a pressing conflict between a pregnant woman and a fetus, whereas limits on stem-cell research merely affect patients who, in theory, might reap medical benefits at some future time.

He also notes that extraction of stem cells can be considered less morally difficult, because it destroys embryos at the very earliest stage, while abortion terminates fetuses that are more developed. But some find destruction of even tiny embryos troublesome because, as Outka puts it, "the requisite genetic information renders them unique . . . begin at this stage."

In the religious world, thinking is varied and sometimes surprising.

The Church of Jesus Christ of Latter-day Saints, for example, is neutral on the subject, though it opposes abortion as unjustified killing except possibly in cases of incest, rape or serious peril to the mother.

The Union of Orthodox Jewish Congregations favors research if it involves frozen embryos that are left over from test-tube baby treatments. And in Islam, many jurists accept work with embryos to seek medical therapies, says Ebrahim Moosa of Duke University.

As with those Muslim thinkers, many believe that the most compelling moral argument for using embryos is that treatments using the highly adaptable stem cells could someday combat dread diseases, even though success is no certainty.

The Religious Coalition for Reproductive Choice advocates full access to abortion on behalf of mainline Protestants, Conservative and Reform Jews, Unitarians and others. The coalition believes the medical potential justifies research that employs the test-tube leftovers or aborted fetuses.

Yet even the position of that group's president, the Rev. Carlton Veazey, is nuanced. He's concerned about programs that create cloned human embryos to destroy them and acquire stem cells, which many in coalition churches find morally problematic. "Should we get into the business of creating and harvesting? I don't think so," he says.

Meanwhile, the California Council of Churches supports a $3 billion state program that involves stem-cell harvesting through destruction of cloned embryos.

On the opposite side of the religious spectrum, the Roman Catholic Church teaches that "the life of every human being is to be respected" once a sperm and egg unite and it vehemently opposes destroying embryos, whether through abortion or for research. Eastern Orthodox and evangelical Protestant leaders generally agree.