Adult-derived stem cell therapies will complement, but they cannot replace, therapies that may be obtained from embryonic stem cells. Still, they do have some advantages. For example-adult stem cells offer the opportunity to utilize small samples of adult tissues, to obtain an initial culture of a patient's own cells for expansion and subsequent implantation in the same person (that is called an autologous transplant). This process avoids immune rejection by the recipient and also protects the patients from viral, bacterial or other contamination from another individual (donor) in case of allogenic transplant. With proper quality control and testing, allogenic adult stem cells may be practical as well. Autologous and allogenic transplants of hematopoietic stem cells (discussed ahead) that are isolated from mobilized peripheral blood or from bone marrow by positive selection with antibiotics are in clinical use. Additionally, since they normally differentiate into a narrow set of cell types, directing them to a desired fate is easier.
          One major disadvantage is that culturing adult stem cells in
-vitro is very difficult and has not been possible for some types. Also they have a very short life, when cultured in-vitro as compared to embryonic cells.