Has antibacterial activity. Specifically expressed in male gonads (Sertoli cells). Not detected at 11.5 dpc. Specific signals are observed within seminiferous cords in male gonads at 12.5, 13.5, 14.5, and 16.5 dpc and in newborn testes. In 16.5 and newborn testes, its expression is also found in epididymis. No specific signal is found in female gonads. Belongs to the beta-defensin family.