Importantly, it has been reported that homozygous mutations in DNAJB13, a radial spoke protein of the mouse ‘9+2’ axoneme that localized to the sperm flagella, cause male infertility, with severe oligo-astheno-teratozoospermia (El Khouri et al., 2016; Li & Liu, 2014). Here, PROS1 is linked to Abnormal sperm morphology.