The Y sex chromosome contains genes that suppress female reproductive axis development and promote male genitalia development.

“The Y sex chromosome has a number of different genes on that chromosome that will suppress, for instance, the development of the female reproductive axis. One good example would be the Müllerian-inhibiting hormone, or MIH. The gene for Müllerian-inhibiting hormone, which is a hormone that prevents the formation of the Müllerian ducts, which is part of the female reproductive structure, well, that gene controls the prevention of the development of the female genitalia and in doing so promotes the development of the male genitalia.”