At approximately day 1

Aromatase and ERβ in Sertoli, Leydig and germ cells; no evidence of ERα through week 24.

Duration: 11 weeks

Reference [PubMed Link]

Boukari K, Ciampi ML, Guiochon-Mantel A, Young J, Lombes M, Meduri G. 2007 Jul. Human fetal testis: source of estrogen and target of estrogen action. Hum Reprod 22(7):1885-92.

At approximately day 1

Approximately 70 primary ducts are evident, some of which exhibit secretory cytodifferentiation.

Reference [PubMed Link]

Cunha GR, Donjacour AA, Cooke PS, Mee S, Bigsby RM, Higgins SJ, Sugimura Y. 1987. The endocrinology and developmental biology of the prostate. Endocr Rev 8:338-362.

At approximately day 1

Testosterone production peaks.

Duration: 2 weeks

Reference

Larsen WJ. 1997. Human Embryology. New York: Churchill Livingstone Inc.

At approximately day 1

Testis weight is approximately 12 mg.

Reference [PubMed Link]

Rabinovici J, Jaffe RB. 1990. Development and regulation of growth and differentiated function in human and subhumand primate fetal gonads. Endocrine Reviews 11(4):532-557.