REC8- and SMC1β-null mutations are sterile because of meiotic failure, whereas Smc1βfl/fl;Gdf9-iCre female mice are fertile, in contrast to the infertility observed in our breeding trials (Xu et al., 2005; Revenkova et al., 2004, 2010; Bannister et al., 2004). The gene discussed is REC8; the disease is Infertility.