DAZ1 and Azoospermia: DAZ genes belong to a greater family of genes, which includes also BOULE (or BOLL, boule-like) and DAZL (deleted in azoospermia-like) genes that map on autosomes and may serve as backup genes, which would help to preserve a residual spermatogenesis in males with AZFc deletions that remove the Y-linked DAZ genes [205].