The Pitt Chronicle examines the state of knowledge and use of placental stem cells: "If we could develop efficient methods that would allow amnion-derived cells to differentiate into specific cell types, then placentas would no longer be relegated to the trashcan. Instead, we’d have a useful source of cells for transplantation and regenerative medicine ... Provided that research advances to the point that we can demonstrate these cells' true therapeutic benefit, parents could conceivably choose to bank their child's amniotic epithelial cells in the event they may someday be needed, as is sometimes done now with umbilical cord blood." These cells share many of the same characteristics as embryonic stem cells.
Link: http://www.umc.pitt.edu/media/pcc/sci1_placentas_2005SEP26.html