Chimeric stem cells

There is growing excitement over stem cell biology. It has stirred strong ethical and moral debates over the status and rights of small clusters of cells. It has promised a panacea for illnesses ranging from diabetes to stroke. It has challenged historical dogmas in developmental biology. There have been many commentaries on all of these issues in prominent journals and newspapers over recent months. In this article, we take a critical look at new data that underpin the last of these claims: the chimeric stem cell.