This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Urethra & Penis, Subject name: Surgery
A 20-year-old female complains of vaginal bleeding. Diagnostic workup reveals clear cell adenocarcinoma of the vagina. A maternal history should be obtained for use of? 
Select and explain. 
A. Thalidomide, B. Oral DES, C. Loss of sensation in the scrotum, D. absent bulbocavernosus refl
B: Oral DES
Answer: B: Oral DES 
Explanation: Oral DES was given to patients who were unable to conceive. Fortunately, this complication is unlikely to occur, because DES has been withdrawn as a drug used for this purpose.