Although the Rnf133 KO mouse model showed significant fertility defects due to abnormal sperm head shape and irregular motility (Figs. 2, 3, and 4), RNF133 protein is likely not a suitable direct male contraceptive target as its ablation in males results in subfertility rather than complete infertility, the latter of which is the desired outcome of an effective non-hormonal male contraceptive. Here, RNF133 is linked to Infertility.