Differentiation potency is the property of a particular cell, such as a stem cell, to give rise to multiple distinct cell types. Three major categories of potency are totipotency, pluripotency, and multipotency. Totipotent cells are capable of differentiating into every cell type of a particular organism in addition to the extraembryonic tissues. An example of totipotent cells is those produced upon the fusion of a sperm and an egg up to the stage of a morula. Pluripotency describes the potential of a stem cell to differentiate into cells comprising any of the three germ layers: ectoderm (gut, lung, etc.), mesoderm (blood, bone, muscle, etc.), and endoderm (skin, nervous system, etc.). Examples of pluripotent stem cells include embryonic stem cells and induced pluripotent stem (iPS) cells. Multipotent cells are those that can differentiate into multiple cell lineages, but only to a restricted family of closely related cell types. Hematopoietic stem cells are an example of...