What are stem cells?

Stem cells are defined by two properties. First, they can “self-renew”, that is they can divide and give rise to more stem cells of the same kind. Second, they can mature or “differentiate” into specialized cells that carry out a specific function.

There are many different types of stem cells. These include embryonic stem cells that exist only at the earliest stages of development; and various types of “tissue-specific” stem cells (sometimes referred to as “adult” or “somatic” stem cells) that are found in various tissues in our bodies. Recently, cells with properties similar to embryonic stem cells, referred to as induced pluripotent stem cells, have been engineered from specialized cells such as skin cells.