This paper reviews our recent laboratory and clinical studies demonstrating the efficacious use of human umbilical cord blood for HLA-matched allogeneic sibling stem/progenitor cell transplantation in cases of Fanconi's anemia. Future implications and potential problems are discussed with regards to (a) the possibility of maternal cell contamination, (b) the broadness of applicability with regards to other diseases that might be transplanted, and whether such transplants are feasible in adults, as well as in children, and (c) the immunological reactivity of cord blood cells, and whether these cells can be used to cross histocompatibility barriers more easily than that of bone marrow from adults.