Which of the following is the least common cause of ambiguous genitalia in a female child?: (A) Fetal placental steroid sulfatase deficiency, (B) Fetal placental aromatase deficiency, (C) Congenital adrenal hyperplasia, (D) WNT-4 gene mutation
Answer is A. Fetal placental steroid sulfatase deficiency is an X-linked disorder therefore occur only in males. So it's the least common cause of ambiguous genitalia in a female child. Ref: Principles and practice of endocrinology and metabolism, Page 957 By Kenneth L. Becker page1061.