Embryonic stem cell cells are multifactorial, meaning they can grow from all the three components of the first three germ layers: the ectoderm, the endoderm, and the mesoderm. In other words, they can grow to more than 200 cell types in the adult body if they are defined to do so. Embryonic stem cells are distinguished by two distinct features: their density, and their ability to double permanently.

ES cells have many variants, that is, they can differentiate into all the components found in the three germ layers: ectoderm, endoderm, and mesoderm.

This includes each of the more than 220 cell types in the adult body. Pluripotency separates embryonic stem cells from adult stem cells obtained from adults; whereas embryonic stem cell cells can produce all kinds of cells in the body, adult stem cells are full and can produce only a limited number of cell types. In addition, under defined conditions, embryonic stem cell cells can proliferate permanently.