Intact primordial, primary, secondary, and antral follicles were all observed in Rnf20Flox/Flox and Zp3‐Rnf20−/− ovaries (Figure S2G,H, Supporting Information), which suggests that female infertility may not be caused by the failure of follicular development but rather by defective oocyte meiotic maturation. The gene discussed is ZP3; the disease is female infertility.