The Mis/Misr2 (Amh/Amhr2) pathway is highly specific to this process, since either ligand or receptor knockout mice present with identical phenotypes of persistent Mullerian duct syndrome (PMDS), a rare form of male pseudohermaphroditism in mice (Behringer et al., 1994; Mishina et al., 1996; Mishina et al., 1999) and humans (Imbeaud et al., 1994). This evidence concerns the gene AMHR2 and persistent Mullerian duct syndrome.