No, stem cells can be very heterogeneous and might have different potential for maturation. In the adult organism, stem cells could be unipotent or multipotent. Unipotent stem cells differentiate into only one cell type. For example, all spermatogonia become sperms. Multipotent stem cells can differentiate into several cell types from the same tissue. For example, hematopoietic stem cells in our bone marrow give rise to diverse blood cells, but not to muscle or brain cells. In the early embryo, cells are pluripotent, meaning that they can give rise to all cell types of the body, but they lose this feature as development progresses. Researchers have established methods to culture embryonic stem (ES) cells and to induce pluripotent stem (iPS) cells from specialized cells.