Interestingly, a much more profound defect in spermatogenesis was observed upon Vasa-Cre mediated Mettl3 or Mettl14 deletion, as SSCs were affected and germ cell development was arrested at the zygotene-like stage, exhibiting the Sertoli cell-only syndrome phenotype in adults [11]. This evidence concerns the gene METTL3 and Sertoli Cell-Only Syndrome.