The anti-mullerian hormone (AMH) plays a very important role in the sexual differentiation of the fetus, which begins around the 8th week of embryofetal development.
Specifically, AMH is synthesized in the male fetal gonad and its function is to prevent the development of the Müllerian ducts. These are the structures that give rise to the uterus and tubes in the female. In contrast, the Wolff ducts develop in the presence of androgens, giving rise to the epididymis, vas deferens and seminal vesicles of the male reproductive system.
In female fetuses, the absence of AMH allows the development of the Müller ducts which eventually become the uterus and fallopian tubes.