Wnts, its receptors and regulators compose complex signaling pathways to regulate cell differentiation, and thus play important roles in the developmental processes. Recent studies have shown that Wnt signaling pathways are also involved in the development of reproductive system such as the formation of Mullerian duct and its derivatives, the development of ovarian follicules and mammary gland during pregnancy, ovulation and luteinization, and the establishment of a normal pregnancy.