Abstract

One of the most‐exciting and controversial discoveries of the last decade has been the isolation of embryonic stem cells from human embryos. The capacity of these cells to form all somatic cell types in the human body has captured the imagination of researcher and clinician alike, the perspectives that they represent for cell replacement therapies in multiple chronic disorders being used to justify the use of embryos for this purpose. However, there is a gradual realization that cell therapies are in the far future and some find that the other, more immediately applicable, types of research give less justification for the use of embryos. Here, cardiomyocytes derived from human embryonic stem cells are discussed. The research opportunities created by having human heart cells available routinely in the laboratory are explored and the types of questions that can be addressed are placed in the context of alternative cell and animal models. BioEssays 29:572–579, 2007. © 2007 Wiley Periodicals, Inc.