This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Sex Intersexuality, Subject name: Gynaecology & Obstetrics
[{'content': 'Most common cause of ambiguous genitalia in a female child is: \nSelect and explain. \nA. Placenta steroid sulfatase deficiency, B. Fetal aromatase deficiency, C. Wnt4 mutation, D. Congenital adrenal hyperplasia', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ans. is d, i.e. Congenital adrenal hyperplasiaRef Leon Speroff 8 th/ed, p349; Dutta Gyne 6th/ed, p440"CAH due to 21 hydroxylase deficiency is the most frequent cause of sexual ambiguity and the M/C endocrine cause of neonatal death." - Ref: Leon Speroff 8th/ed, p349Ambiguity of sex at birth -- "Cases of ambiguity of sex detected at birth are due to adrenogenital syndrome unless proved otherwise". - Ref: Dutta Gynae 6th/ed, p404', 'role': 'assistant'}]