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.