During differentiation, pluripotent cells make a number of developmental decisions to generate first the three germ layers (ectoderm, mesoderm and endoderm) of the embryo and intermediate progenitors, followed by subsequent decisions or check points, giving rise to all the bodys mature tissues. The differentiation process can be modeled as sequence of binary decisions based on probabilistic or stochastic models. Developmental biology and embryology provides the basic knowledge of the cell types differentiation through mutation analysis, lineage tracing, embryo micro-manipulation and gene expression studies. Cell differentiation and tissue organogenesis involve a  limited set of developmental signaling pathways. It is thus possible to direct cell fate by controlling cell decisions through extracellular signaling, mimicking developmental signals.