JOHN KERRY'S recent assertions about stem cell research are so obviously untrue and so easily refuted that he must on some level actually believe them--as only an ideologue can. He claims repeatedly that President Bush has "enacted a far-reaching ban on stem cell research"; in fact, the Bush administration provided over $200 million for stem cell research last year, including $25 million for embryonic stem cell research. He claims that stem cells will one day cure Alzheimer's disease, an ailment that uniquely terrifies the baby-boom generation. But leading scientists, including enthusiastic supporters of stem cell research, have made it clear that stem cells will not help treat Alzheimer's. Kerry claims that stem cell cures are "at our fingertips" and that "help is on the way," when in fact there has not been a single human trial of an embryonic stem cell therapy.

Unlike the war in Iraq, where Kerry maneuvers to play both sides, stem cells are an issue where he brooks no ambiguity. He is for progress; President Bush is against it. He will end suffering; President Bush will leave the sick to "look to the future with fear." As William Saletan noted in a recent piece in Slate, Kerry has made biomedical advance a religion, and stem cells are his gospel. Understanding how this religion works--why it inspires so much anti-Bush ire and pro-Kerry enthusiasm, why it appeals to an aging and anxious population, and where it would lead America if it became our national faith--should be a priority as

The issue of stem cells is scientifically and ethically complex. Stem cells are undifferentiated and self-replicating cells with the potential to become the differentiated cells that make up the various tissues in the human body. Laboratories acquire them from many sources: bone marrow, umbilical cord blood, aborted fetuses, embryos, cloned embryos. Stem cells harvested from adults for purposes of medical research are ethically unproblematic; research on such cells garners near-universal support and receives over $180 million per year in funding from the National Institutes of Health. Embryonic stem cells, harvested from human embryos which are destroyed in the process, are fraught with ethical peril--and that is the reason we are having a far-reaching debate.

Most scientists believe that embryonic stem cells hold the greatest medical promise. Just as a tiny embryo can develop into a baby, with all its exquisitely specialized organs and parts, so embryonic stem cells can become virtually any type of human cell, with a facility seemingly greater than adult stem cells. But embryonic stem cell research is in its earliest stages, and no one knows whether these powerful cells can be directed in ways that are therapeutically useful. Moreover, it is hard to say whether the scientific establishment, in its political quest to secure more funding and stave off regulation, is overstating the promise of embryonic stem cells and understating the promise of non-embryonic stem cells. Nevertheless, one cannot deny the scientific potential of embryo research, or the large stake the scientific community now has in its success.