Androgen Insensitivity Syndrome

With an understanding of normal sexual development, consider the consequences of complete androgen insensitivity on the events of development in a person with the XY genotype. Since the Y chromosome is present, there will be testes. The testes will produce testosterone and AMH. AMH will cause degeneration of the Müllerian ducts, and so there will be no fallopian tubes, uterus, cervix, or upper vagina. But the defective receptor means that testosterone cannot exert its effects, so the Wolffian ducts also degenerate, and there will be no vas deferens. There will also be no penis or scrotum. Instead, the testes remain in the abdomen (where they originate), and the exterior tissue develops a short vagina that ends in a blind pocket. In milder forms of the syndrome, with only partial insensitivity to androgens, the genital structures may be ambiguous, with varying degrees of male versus female predominance.