The term “stem cell” is a broad one that includes many types of cells from many tissue origins. Although current advances in stem cell research and technology show that stem cells may have therapeutic potential, many unanswered questions remain and other new questions emerge. For example, each type of stem cell has specific attributes, and it is not yet known which cell type is the “best” for treatment after SCI. Also, questions of dosage (i.e. how many cells and what time after SCI) and safety in humans have not yet been answered in clinical trials. Thus, more research is vital to understand the potential and application of this promising approach. It is an exciting time for stem cell research, but many crucial questions on the use of stem cells remain. As there are many features of the use of stem cell transplant therapy that remain unknown, it is impossible to provide a definitive timeline.