Transabdominal testicular descent is really ovarian ascent

Some investigators have suggested that testicular descent relative to the ovary is actually caused by the relative upward growth of the structures adjacent to the testis and that in the early phase of descent the testis is anchored to the inguinal region as the embryo enlarges. This concept was founded on results from the dissection of human fetuses. In this study the development of the urogenital system in fetal mice is examined using scanning electron microscopy to determine the distance between the bladder neck and the lower pole of the gonad. The results of this study confirm that transabdominal descent of the testis relative to the ovary is in one sense really ascent of the ovary in the fetal mouse, while the testis is anchored to the inguinal region by the developed gubernaculum. The testis shows real movement at the beginning of the inguinoscrotal phase of testicular descent at birth.