SPATA16 and Globozoospermia: However, semen quality of homozygous bulls is not as severely compromised as, e.g., in males with globozoospermia [25, 26] and spermatogenic arrest [61], respectively, due to loss-of-function alleles in human and murine SPATA16. It is plausible that the SPATA16:p.Ile193Met variant compromises semen quality in the homozygous state, as the methionine at position 193 is predicted to be deleterious to SPATA16 function.