Based on limited published evidence, WFDC10B is a WAP four-disulfide core domain protein with predicted serine-type endopeptidase inhibitor activity and protein binding capability. GO annotations indicate involvement in antibacterial humoral response and innate immune responses. WFDC10B is part of a conserved reproductive tract-specific gene cluster on chromosome 20. Recent CRISPR/Cas9 studies demonstrated that deletion of multiple WFDC genes, including WFDC10B, resulted in male infertility characterized by defects in sperm motility and increased sperm death, despite normal spermatogenesis 1. These findings suggest WFDC10B contributes to male reproductive function.