.....Here we describe a stepwise protocol for the generation of eggs from mouse PSCs, such as embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs). ESCs and iPSCs are first induced into primordial germ cell-like cells (PGCLCs) that are in turn aggregated with somatic cells of female embryonic gonads, the precursors for adult ovaries. Induction of PGCLCs followed by aggregation with the somatic cells takes up to 8 d. The aggregations are then transplanted under the ovarian bursa, in which PGCLCs grow into germinal vesicle (GV) oocytes in ∼1 month. The PGCLC-derived GV oocytes can be matured into eggs in 1 d by in vitro maturation (IVM), and they can be fertilized with spermatozoa by in vitro fertilization (IVF) to obtain healthy and fertile offspring. This method provides an initial step toward reconstitution of the entire process of oogenesis in vitro.