Targeted deletion of pRB from prenatal germ cells results in germline ablation and infertility (44, 53, 54), and focal GCNIS-like (germ cell neoplasia in situ) like cells are only observed when pRB is deleted from progenitors and/or differentiating spermatogonia, arguably due to inability to commit to the spermatogenic lineage (54), an interpretation that might have some merit given that progenitor-Aundiff are enriched for pluripotency-associated transcripts (36). Here, RB1 is linked to Infertility.