Totipotent stem cells; zygote + 2 to 4 cell embryo These cells are capable of giving rise to the entire organism (both embryonic and non-embryonic tissues) Multipotent stem cells; adult stem cells   Pluripotent stem cells; embryonic stem cells and embryonic germ cells These cells can give rise to derivatives of all 3 germ layers [embroynic tissue only and not extraembryonic tissues] Embryonic stem cells (ESCs) have the potential to form any cell type in the body. Pluripotent stem cells (PSCs) can be divided into 2 types [a] Embryonic stem cells (ESCS): derived from the inner cell mass of the mammalian blastocyte. [b] Induced pluripotent stem cells (iPSCs): somatic cells reprogrammed to a pluripotent state by exogenous expression of transcription factors responsible for conferring pluripotency on ESCs.

Table 1: Classification of stem cells based on their potency and their sources.