Issues in human embryonic stem cell biology.

Human embryonic stem cells (hESCs) derived from frozen unused blastocytes from in vitro fertilization clinics exhibit unlimited proliferative capacity, and are pluripotent. The ability to maintain hESCs cultures in an undifferentiated state in vitro and differentiate them along a given lineage in a controlled manner make these cells potentially invaluable in regenerative medicine. Recent developments in the generation of patient-specific hESCs as well as animal product-free culture systems are some of the latest developments in the field; however great challenges lie ahead before the therapeutic application of hESCs becomes a reality. This article addresses some of the successes and roadblocks concerning the hESCs field; including various political, ethical and scientific obstacles.