Loss of KIF18A function in mice leads to recessive infertility with variable penetrance, ranging from 90% penetrance on the wild derived inbred strain background, CAST/EiJ (CAST) to 37% penetrance on the common laboratory inbred strain background C57BL/6J (B6) (Reinholdt, Munroe et al. 2006). Here, KIF18A is linked to Infertility.