Pseudohermaphroditism in a female child is most commonly due to -: (A) 21 α hydroxylase deficiency, (B) 17 α hydroxylase deficiency, (C) 11 β hydroxylase deficiency, (D) 3 β Hydroxysteroid dehydrogenase deficiency
Answer is A. Classic 21 α hydroxylase deficiency is the most common cause of Ambiguous genitalia in a new born.

Pseudo hermaphroditism

A congenital abnormality of the external genitalia and of the body in which one possesses sex glands of one sex but genitals of the opposite sex.