Since the discovery of PLCZ1 in 2002, a significant body of research has demonstrated the fundamental role of PLCZ1 as the sperm-specific oocyte activation factor and have provided strong evidence to support a causal link between PLCZ1 deficiency and male infertility (Saunders et al. 2002, Sanders & Swann 2016, Swann & Lai 2016, Parrington et al. 2019). This evidence concerns the gene PLCZ1 and male infertility.