Stem Cells... An Emerging Portrait

From the noise that's been made about them, stem cells sound as if they're poised to change the face of biomedicine. That will only be true, however, if researchers can figure out just what they are, and that portrait is just emerging, as the story on the following pages demonstrates. Find out what it takes to keep embryonic stem cells happy in culture onpage 18, and follow along as researchers debate the potential of adult stem cells onpage 20. Finally, Stephen A. Bent discusses the omnipresent legal and ethical challenges involved in stem cell use onpage 22.

Human embryonic stem cells remain the focus of an ever-intensifying public debate that blurs the limits of biology, confusing cultured tissues with children, and blastocysts descended from fertilized ova with those derived from somatic cell nuclei. When Woo Suk Hwang's group from Seoul National University published controversial findings two months ago, they used ...