MLH3 and Infertility: Similar to the situation seen for Mlh3-/- males [29], Mlh3DN/DN males show complete infertility, accompanied by significantly reduced testes size when compared to WT (Fig 1A and 1B; p < 0.0001) and the absence of spermatozoa in the epididymides (Fig 1C; p < 0.0001).