Germline stem and progenitor cells (GSPCs), including primordial germ cells (PGCs) and germline stem cells (GSCs), generate various states of germ stem cells and then differentiate into spermatozoa and ova to produce offspring. GSPCs also self-renew to generate more stem cells. The cell fate determination of GSPCs is regulated by a multitude of mechanisms such as the changes at the level of translation, transcription, and epigenetic modifications. Germline-specific expression pattern is likely to be observed in these factors which are essential for GSPC self-renewal and differentiation.