Gonads, Male: Stem and Progenitor Cells in Adults

There are several classes of stem cells and they are often categorized based on the number of types of cells into which they are able to differentiate. The only cells considered truly totipotent may be the fertilized egg and those cells into which the single cell divides in the first few hours after fertilization. These cells have the potential to create an entire organism. Human pluripotent stem cells, such as embryonic stem cells isolated from the embryonic blastocyst, and induced pluripotent stem cells (iPSC) are able to differentiate into all types of the cells making up the human body, with the exception of placenta. Recent progress in stem cell research has allowed for the in vitro differentiation of these cells into primordial germ cells as ...