This chapter addresses the current status of fetal stem cell therapy, its limitations and its future development. Haematopoietic stem cells (HSCs) from cord blood have greater proliferative capacity than their adult counterparts but are limited in number. Fetal MSC (mesenchymal stem cells) have properties intermediate between embroyonic stem cells (ES) and adult stem cells and can be derived from a range of pregnancy-related tissues, including first-trimester fetal blood, liver and bone marrow, second-trimester liver, lung, pancreas, bone marrow and amnotic fluid, placenta, cord and membranes. A wide range of metabolic and haematological disorders in children can now be successfully treated by bone marrow transplantation (BMT). Number of animal models of human diseases suitable for fetal stem cell therapy have been investigated, particularly muscular dystrophy and osteogenesis imperfecta. Clinical trials using MSCs will require ready access to safe and functionally intact cells in sufficient numbers for transplantation into human patients.