Swyer synrome, or XY gonadal dysgenesis, is a type of female hypogonadism in which no functional gonads are present to induce puberty in an otherwise normal girl whose karyotype is then found to be XY. Her gonads are found to be nonfunctional streaks. Estrogen and progesterone therapy is usually then commenced. The gonads are normally removed surgically because they do not function and may develop cancer.