IZUMO1 and male infertility: Considering our previous work showing that IZUMO1 can mediate cell-cell fusion (Brukman et al., 2023) and that significantly lower levels of this protein were detected in the sperm cells of patients with total fertilization failure (Enoiu et al., 2022), we expect that the SPICER assay will be able to resolve some unexplained cases of male infertility that result from loss of function of components of the fusion machinery.