Ever since they were first isolated two years ago, embryonic stem cells have been touted as a potential medical miracle. Diabetes, Parkinson's disease, Alzheimer's and spinal-cord injury are among the devastating maladies that might be treated by turning these versatile cells into healthy replacements for just about any damaged tissue, from the pancreas to the brain.
But for many people, using embryos for anything besides making humans is morally repugnant. And Congress prohibits any federal funding of research on fetal tissue. Now that ban may be skirted.
Under new guidelines issued last week by the National Institutes of Health, government-funded scientists...