When we talk about stem cells, we are actually talking about a complicated series of things, including adult stem cells which are largely cells devoted to replacing individual tissues like blood elements or liver or even the brain.

Baltimore is a member of The Jackson Laboratory's Board of Trustees the Bulletin of the Atomic Scientists' Board of Sponsors the National Academy of Sciences USA (NAS) the NAS Institute of Medicine (IOM) Amgen Inc. Millikan Professor of Biology at Caltech. Baltimore however refused to retract the paper.

David Baltimore (born March 7 1938) is an American biologist university administrator and Nobel laureate in Physiology or Medicine. He served as president of the California Institute of Technology (Caltech) from 1997 to 2006 and is currently the Robert A.