My concept of cell differentiation involves genetic information from DNA being transcribed into mRNA proteins-morphogenes (mRNAs+ homeodomain proteins)-and stored in the ovoplasm as maternal inheritance, or cytoplasmic genetic memory. Feedback mechanism(s) allow these morphogenes to selectively unlock new genes, regulating the development of the embryo. The blastomeres and the embryonic pluripotent cells of the inner cell mass of early (5 day) blastocysts are loaded with morphogenes which hamper the production of cell lines and are responsible for the formation of embryoid bodies in vitro and teratomas in vivo. There are therefore legitimate concerns as to proposals to use embryonic pluripotent cells for cell therapy and regenerative medicine. An alternative cell therapy would involve the production of tailored growth-related genes-morphogenes-and hence selective in vitro differentiation of adult de-differentiated cells.