May play a role in spermatogenesis. Expressed predominantly in testis (at protein level). Expression is lower in patients with obstructive azoospermia than in fertile controls and is not detected in patients with non-obstructive azoospermia. 60-fold stronger expression found in adult than fetal testis. Detected in spermatocytes and round spermatids of the seminiferous tubule. Belongs to the SPATA25 family.