(A) Formation of the Wolffian (mesonephric) duct, which by 24 days has grown caudally to join the cloaca. At 5 to 6 weeks the paramesonephric (Müllerian) ducts appear as invaginations of the coelomic epithelium. At 7 weeks (B) the MDs have grown caudally towards the urogenital sinus. Subsequently (C, 8 weeks), the opening of the MDs into the coelomic cavity is fimbriated, and with further growth the MDs reach the UGS, while the Wolffian ducts degenerate. Modified from (Park, 2016) with permission.