◾️ Androgen is critical for the development of the male external genitalia. Removal of the testes, which stops androgen release, will result in the feminization of the external genitalia. Exposure of a female fetus to androgens will masculinize her external genitalia.

In the presence of the androgen DHT, the primordial genital structures will fuse to form the penis, which encloses the urethra and the scrotum. In the absence of any hormonal influence, the primordial genital structures will not fuse and will therefore form the female genitalia instead.

◾️ All embryos will inherently develop along the female pathway. Some XY individuals have reproductive tissues  that don't respond to the presence of androgens (androgen insensitivity) and they can suffer from testicular feminization mutation (TFM).

Because Y chromosome is present, testicular development occurs and testes also produce MIF causing the regression of Mullerian duct system. However, in these individuals, the Wolffian duct system doesn't recognize androgen and therefore, doesn't develop. 

◾️ Males born with TFM have perfectly normal-appearing external female genitalia and are generally reared as girls. The parents and doctors are often unaware that the child is actually genetically male. This condition is usually discovered during adolscence when menstruation fails to occur. Because the Mullerian ducts fails to develop, they have short vagina and no uterus/fallopian tube will develop.

In these individuals, estrogen receptors function normally. At puberty, the estrogen generated from excess androgens initiate the development of the secondary sex characteristics in a female direction.