Talk:Development Animation - Testis Descent

http://www.eje-online.org/cgi/content/full/159/suppl_1/S75

Data from a recent study of male human fetal (between 10 and 35 weeks) gonad position.

10 to 23 weeks - (9.45%) had migrated from the abdomen and were situated in the inguinal canal

24 to 26 weeks - (57.9%) had migrated from the abdomen

27 to 29 weeks - (16.7%) had not descended to the scrotum

A second study showed that from 33 weeks fetal testes had descended to the scrotum and that between 33 to 40 weeks (term) both testes have normally descended to the scrotum. Failure of descent (cryptorchidism) either unilateral or bilateral testicular descent, occurring in up to 30% premature and 3-4% term males. (More? BGDlab - Genital Abnormalities | Notes - Genital Abnormalities)

References: Sampaio FJ, Favorito LA. Analysis of testicular migration during the fetal period in humans. J Urol. 1998 Feb;159(2):540-2. | Malas MA, Sulak O, Ozturk A. The growth of the testes during the fetal period. BJU Int. 1999 Oct;84(6):689-92.