Essential for normal spermatogenesis and male fertility. Testis-specific. Highly expressed in spermatocytes (at protein level). Male mice are infertile with smaller testis and epididymis, but female mice retain normal fertility (PubMed:31930642). Spermatogenesis in the male mouse is arrested at the spermatocyte stage, and no sperm is found in the epididymis (PubMed:31930642). Germ cells apoptosis is increased without changes to the serum concentration of testosterone, LH, and FSH or synapsis and recombination during meiosis (PubMed:31930642).