BMP15, or GDF9B is a member of the bone morphogenetic protein family which is part of the transforming growth factor-beta superfamily that are involved in embryonic development and adult tissue homeostasis. BMP15 is expressed exclusively in the oocyte. It is an oocyte-specific growth/differentiation factor that may be involved in oocyte maturation and follicular development. Defects in BMP15 are the cause of ovarian dysgenesis type 2. BMP15 could be used as an oogenesis marker to track human amniotic fluid stem cells differentiation into the oocyte-like cells.Synonyms: BMP-15, Bone morphogenetic protein 15