So far as we know, there is no concerted effort to prevent couples from discarding unused embryos they've stored in a fertilization clinic's freezer. Yet letting those same couples donate the embryos for use in stem-cell studies is seen by many as unethical because the embryos are destroyed in the course of the research.

One who sees it that way is President Bush, who promised again to veto a bill, passed last Thursday in the House, that would lessen federal funding restrictions on embryonic research. Bush has frequently expressed the hope that new techniques will be discovered to render the embryo issue moot, and last Thursday's news included a story laying out the same hope.

Researchers reported that they'd successfully reprogrammed skin cells from mouse tails to create viable stem cells. Then, as cell biologist Kenneth Miller explained on PBS' "NewsHour," they put them to what you might call the acid test, which is to see whether or not these cells could develop into all the tissues in the body and, in one case . . . "actually become fully functional adult organisms, and these cells passed every single test."

Miller called it "still a highly experimental technique," adding, "You might refer to it as proof of concept. . . . The concept is that unlocking the developmental potential of a cell doesn't require an embryo." And that would solve the ethical and political debates. But such an unlocking may be a decade or longer away, which brings us back to the bill headed for the president's veto pen. Supporters don't have the votes for an override, so federal funds will continue to be off-limits to researchers using any but a few approved lines of embryonic cells.

The political debate has split Americans, and not always by political party.

Former first lady Nancy Reagan, for example, has been a leader in seeking more embryonic research, along with other prominent Republicans.

It will be a great day when scientific developments render the political argument moot. In the meantime, however, progress toward needed therapies is slowed as unused embryos are destroyed straightaway rather than diverted first to this vital area of research.