Biomedical science can offer us tremendous benefits, but only if we make sure they do not come at the cost of our highest ideals.

Op-Ed article by Yuval Levin, former director of President's Council on Bioethics, says ethical questions at heart of stem cell research debate are being buried beneath hype and confusion; says Bush administration has spent more than $100 million in embryonic stem cell research that is promising but still speculative and American scientists hold huge lead in field; suggests positions can be reconciled, that 'pluripotent' cells could be developed without harming human embryos (M)...