Transcriptional regulator that plays a key role in germ cell development. Determines the oogenic fate by activating key genes for the oogenic program and meiotic prophase entry. Acts downstream of bone morphogenetic protein (BMP) by regulating expression of genes required for the oogenic programs, which are repressed by Polycomb activities in sexually uncommitted germ cells. Regulates expression of STRA8, a central downstream effector for the meiotic program. Acts independently of retinoic acid (RA). In males, not required for germ-cell sex determination, but required to allow the spermatogonia to efficiently accomplish the meiotic prophase.