Gametogenesis: Primordial germ cells; Mitosis and Meiosis; Maturation of the female gamete; Imprinting and epigenetic regulation; Fertilization; Oocyte activation -- Early embryo development: Syngamy and spindle formation; Cleavage, compaction and blastulation; Cell commitment and Waddington model of epigenetic restriction.  Asymmetric imprinting; Establishment of the body axis -- Stem cells and gametogenesis: Oocyte competence and potency; Oocyte as a source of uniparental pluripotent cells; Spindles of uniparental origin in mammals; Stem cells as a source of oocytes.

This Brief offers a concise, handy overview of the main concepts related to Embryology, revisited through the novel concepts that are applied daily in stem cell research and cell therapy oriented investigations. It is based on three main areas:   -The process involved in female gamete differentiation and maturation. The main aspects related to cell biology will be covered and an overview of the epigenetic regulation of gametogenesis will be presented.   -Early stages of embryo development with a careful analysis of the regulatory mechanisms driving cleavage, polarization and genome activation. -Stem cell and gametogenesis. The use of the oocyte as a possible source for the derivation of stem cell lines is discussed and depicted as a powerful tool to investigate oocyte potency and asymmetric imprinting. The potential biological  implications are evaluated and use of stem cells to derive oocytes is presented.