Deleterious variants in human FANCM lead to oligoasthenozoospermia [34] or Sertoli Cell-Only Syndrome, where only Sertoli cells outline the seminiferous tubules, with no sperm detectable [35], and Fancm-null male mice show reduced proliferation and loss of PGCs [36]. This evidence concerns the gene FANCM and Sertoli Cell-Only Syndrome.