Sexual Development - Biology Gonadectomy in utero of embryonic rabbits shows that testes impose male phenotypic events on embryo Sex determination, the control of events leading to development of gonadal, primary sex, is controlled by specification of male gonadal development. Sex differentiation, subsequent development of the genital tract, is an endocrine controlled response to the type of gonad present. Wolffian ducts are progenitors of male accessory structures, epididymis, vas deferens and seminal vesicle. Mullerian ducts are progenitors of female accessory structures, uterus, fallopian tubes and vagina.
Testes develop prior to ovaries.
Sertoli cells differentiate and produce anti- Mullerian hormone which causes regression of Mullerian ducts. Leydig cells differentiate and produce testosterone which stimulates Wolffian ducts to differentiate into internal male structures. Converted to dihydrotestosterone which mediates masculinization of urogenital sinus and external genitalia. Testes can differentiate in the absence of germ cells - importance of somatic Sertoli cells. Ovary development definitive at 3 months gestation when oogonia enter meiosis.