In mouse TGFBR-1 knock-out models, the female mice were sterile. They developed oviductal diverticula and defective uterine smooth muscle, meaning that uterine smooth muscle layers were poorly formed. Oviductal diverticula are small, bulging pouches located on the oviduct, which is the tube that transports the ovum from the ovary to the uterus. This deformity of the oviduct occurred bilaterally and resulted in impaired embryo development and impaired transit of the embryos to the uterus. Ovulation and fertilization still occurred in the knock-outs, however remnants of embryos were found in these oviductal diverticula.