Human stem cells are unspecialized cells that can be found throughout the body. They have the power to differentiate into any cell in an organism and to self-renew. Stem cells can be found in both embryonic and adult cells. Specialization can be broken down into multiple stages. Each stage reduces developmental potency, which means that a unipotent stem cell can't differentiate into as many different types of cells as a pluripotent one.
Developmental biology (which includes embryology) has been termed the "stem cell of biological fields." Developmental biology is the ancestor of genetics, cell biology, cancer, immunology, evolutionary mechanisms, neuroscience, and systems biology. Furthermore, developmental biology is still going strong, spawning new disciplines while maintaining its own character. The developmental viewpoint is being reasserted as a major research topic in many disciplines, including evolutionary biology and oncology.