t he psychoendocrinology of the development of gender identity in patients with congenital adrenal hyperplasia (caH) is poorly understood.prenatal androgen exposure, postnatal hormonal influence, degree of external genitalia virilization, genital appearance, social rearing and other biological factors, are all thought to have an effect on gender identity development. [1]2][3][4][5][6] Late diagnosis and referral, which are common problems in our country, might have an adverse effect on normal gender identity development in female patients with caH. 7 We describe two genetically female sisters with caH secondary to 11-hydroxylase deficiency who were raised as boys and referred at the age of puberty to our clinic.We believe that the gender identity development in these two patients, who had the same medical and social background, was related to the extent of external genitalia virilization.