Embryonic stem cells are originated from the inner cell mass of a blastocyst are pluripotent stem cells  Human embryos can reach the blastocyst stage of 4–5 days post fertilization, in which they consist of 50–150 cells  Researchers are presently focusing heavily on the therapeutic potential of embryonic stem cells  Embryonic stem cells are able to generate primitive ectoderm, which ultimately distinguish during gastrulation into all acquired parts of the three primary germ layers: ectoderm, endoderm, and mesoderm  The germ layers generate more than 220 cell types in the adult human body  Due to the plasticity and unlimited capacity of the embryonic stem cells the therapies have been proposed for regenerative medicine  It can also be utilized in drug discovery, Models of genetic disorder, repair of DNA damage and in clinical trials