Biology and common sense alike tell us that we are dealing with human life in its earliest form. With implantation and luck (about 40 percent of embryos fail to survive naturally) each will become a genetically unique person like you and me. The ethical questions then become clear: what value should we place on human embryos, and how should their well-being be balanced with that of the millions whose acute suffering might be alleviated through stem-cell research and development? These issues are further complicated by the fact that the embryos immediately in question are all products of in vitro fertilization and most will eventually be discarded anyway.

Like most proponents of the “right to life,” the Roman Catholic Church has at least been ethically consistent. Despite in vitro fertilization’s benefits to infertile couples, the church opposes the procedure precisely because so many human embryos are automatically destined for destruction. Moreover, the church remembers how Nazi doctors experimented on Jewish prisoners who were first denied their dignity and rights as human beings and then–like the surplus human embryos–destined for fast or slow extinction. It fears the slippery slope.

But most Americans are more pragmatic, if not outright utilitarian. Many are inclined to believe that the good that stem-cell research promises to produce outweighs the limbolike life of unwanted human embryos now in cold storage. Sympathy naturally affects individual outlooks. A mother suffering from Alzheimer’s understandably elicits more compassion than a stranger’s anonymous fertilized egg.

When professional ethicists debate the shoulds or shouldn’ts of public policy, personal feelings carry no weight. Neither do appeals to Scriptures or other religious authority. Even arguments of abstract moral principle, like whether noble ends ever justify ignoble means, must be tempered by considerations of concrete circumstances and probable outcomes. Thus some ethicists argue that respect for human life at least requires scientists to exhaust the therapeutic potential of adult stem cells–a procedure that no one finds objectionable–before extracting those from embryos.

The real danger in this debate is the almost irresistible tendency to treat human embryos as “property” ripe for commercial exploitation. After all, the interested parties are not isolated individuals arguing–as with abortion–over a private “right to choose.” Nor are the beneficiaries just the sick, the aged and the prematurely infirm. Those who will benefit first are the research universities seeking funding and prestige, the pharmaceutical companies seeking new products and investors–and prominent scientists who often have financial interests in both. The federal government also has a stake: in the race to market therapies for degenerative diseases, the United States is in competition with Britain and other countries where concern about experimenting with human life is less pronounced.

In this wider context, the voices of religion are naturally more skeptical of promised biomedical miracles than are the scientists themselves. Mindful of human sin and the hubris of the powerful, religious ethicists are wary of any proposals that might exploit the weak to benefit. By contrast, the voices of biotechnology are Promethean, proactive and impatient with ethical restraints. Both need to exercise wisdom and prudence, always in short supply. Both stand at the edge of a new world where human beings can virtually reinvent themselves. Together with politicians and the people, they must decide what is really meant by human life and progress.