Scientists at the Salk Institute have been able to reprogram cord blood stem cells to make them very similar to embryonic stem cells.
Embryonic stem cells are very valuable because they can theoretically be turned into any type of cell. They are controversial because embryos must be destroyed to harvest them. Using reprogrammed adult stem cells is not ideal since many of these adult cells have undergone mutations.
That is what makes this success so significant. Cord blood stem cells are primitive cells with no mutations. If they can be reprogrammed to become any type of cell, the possibilities are endless.