In Vitro Production of Germ Cells from Stem Cells: Hypes and Hopes

Several lines of evidence have reported that mouse ESCs can successfully differentiate into primordial germ cells (PGC) as well as into mature male and female gametes. Human ESCs and adult stem cells (ASCs) can also differentiate into PGCs. Differentiation of ESCs into germ cells of various stages seems to be a spontaneous and quick process, probably due to the nature of ESCs themselves and the microenvironment of the culture conditions that favor this process. Although the functionality of these ESC-derived gametes remains to be established, derivation of both male and female gametes from ESCs raises the possibility of using these gametes to gain a better understanding of basic reproductive biology and, in particular, in conjunction with nuclear transfer technology, to extend the potential for therapeutic cloning and the treatment or infertility.