SPAG17 and Reduced sperm motility: Although SPAG17 showed a ‘limited’ association with asthenozoospermia according to IMIGC, IDDB reported four variants associated with asthenozoospermia or azoospermia, and the knock-out (KO) mouse models for this locus showed reduced sperm numbers with altered motility and morphology despite a normal reproductive system (Xu et al., 2018; Abdelhamed et al., 2020).