<s>[INST] context: Congenital adrenal hyperplasia The early development of the genital system is similar in both the sexes. Congenital defects in sexual development. usually arising from a variety of chromosomal abnormalities tend to present clinically with ambiguous external genitalia. These conditions are known as intersex or hermaphroditism. True hermaphroditismdeg : Individuals with this disorder have both ovarian and testicular tissue, most commonly as composite ovotestes but occasionally with an ovary on one side and testis on the other. Pseudo hermaphroditismdeg : The genetic sex indicates one sex whereas the external genitalia has characteristics of the other. Pseudo hermaphroditism is caused by either abnormal levels of sex hormones or abnormalities in sex hormone receptor. Female pseudohermaphroditism Genetic females (gonads ovaries) with masculinized external genitalia manifesting as - clitoral hyperophydeg and some degrees of fusion of urogenital or labioscrotal folds. Male pseudohermaphroditism Genetic males (Gonads testis) with feminized external genitalia manifesting as hypospadiasis, or incomplete fusion of the urogenital or labioscrotal folds of female pseudohermaphroditism Congenital adrenal hyperplasia (M/C cause)deg : 21 - hydroxylase (P450c21) deficiencydeg 113 - hydroxylase (P450c11) deficiencydeg 3 [3 - hydroxysteroid dehydrogenase deficiencydeg Elevated androgens in maternal circulation due drug intakedeg - testosterone, danazol norethindrone Maternal virilising ovarian tumourdeg Aromatase (P450arom) deficiencydeg Causes of male pseudohermaphroditism Androgen insensitivity syndrome (Androgendeg receptor abnormalities : 5tx - reductase deficiencydeg Testosterone biosynthesis defects 3 3 - hydroxysteroid dehydrogenase deficiencydeg 173 - hydroxylase (P450c17) deficiency deg 173 - hydroxysteroid dehydrogenase deficiencydeg Congenital lipoid adrenal hyperplasia (STAR deficiency)deg Gonadotropin - resistant testes Anti - mullerian hormone deficiency [/INST] question: Commonest cause of female pseudo hermaphroditism is : | options: A: Virlizing ovarian tumor B: Ovarian dysgenesis C: Exogenous androgen D: Congenital adrenal hyperplasia | answer: D </s>