Embryonic development is a tightly regulated process that produces from a single zygote the some 400 different tissues and cell types forming the human body. The differentiation program of embryogenesis is under the control of transcription factor networks in the context of significant changes in the epigenetic landscape. A master example of these epigenomic (re)programing processes resulting in changes in DNA methylation and histone modification patterns is the formation and development of PGCs into gametes (oocytes and sperm). The method of cellular reprograming of somatic cells into induced pluripotency by the ectopic expression of the master transcription factors OCT4, SOX2, KLF4 and MYC bears not only the potential to regenerate diseased organs but also provides further insight into the principles of epigenetic control of cellular differentiation. Epigenomic changes and key transcription factors are also involved in the homeostasis of regenerating tissues, such as skin and blood, in which adult stem cells constantly differentiate, in order to restitute lost cells.