Author Affiliations: Division of Genetics, Departments of Pediatrics, Obstetrics, and Gynecology, Tufts-New England Medical Center and Tufts University School of Medicine, Boston, Mass (Dr Bianchi) and Queen Charlotte's & Chelsea Hospital and Institute of Reproductive and Developmental Biology, Imperial College London, Hammersmith Campus, London, England (Dr Fisk).
The current ethical, political, and scientific debates on stem cells pitch the benefits and limitations of 2 cell types against each other, adult vs embryonic stem cells. Embryonic stem cells derived from human blastocysts have the key advantage of pluripotency, meaning that they form nearly all cell types but also have the disadvantage of forming tumors in vivo, which may limit clinical application to tissue engineering rather than cell transplantation. In contrast, adult stem cells are derived from mature tissue, typically from bone marrow, but increasingly from most organs. In general, adult stem cells have low plasticity, although reports of differentiation outside traditional lineage boundaries suggest that some adult stem cells may be more pluripotent rather than multipotent.1
Bianchi DW, Fisk NM. Fetomaternal Cell Trafficking and the Stem Cell DebateGender Matters. JAMA. 2007;297(13):1489-1491. doi:10.1001/jama.297.13.1489