Androgen insensitivity syndrome (AIS), formerly known as testicular feminization, is an X-linked recessive condition resulting in a failure of normal masculinization of the external genitalia in chromosomally male individuals. Adolescent patients have no pubic and axillary hair, with otherwise scanty body hair, and lack acne, although breasts are normal as a result of conversion of testosterone to estradiol. Mullerian agenesis is characterized by a failure of the mullerian ducts to develop, resulting in a missing uterus and fallopian tubes and variable malformations of the upper poion of the vagina. An individual with this condition is hormonally normal; that is, they will enter pubey with development of secondary sexual characteristics including thelarche and adrenarche (pubic hair). Gonadal dysgenesis is characterized by a progressive loss ofprimordial germ cells on the developing gonads of an embryo.The accompanying hormonal failure also prevents the development of secondary sex characteristicsin either sex, resulting in a sexually infantile female appearance and infeility. Failure to develop secondary sex characteristics (sexual infantilism) is typical in Turner's syndrome.