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 6-month-old boy was born with hypospadias. This condition is due to failure in the development of which of the following? 
Select and explain. 
A. Urogenital fold, B. Mullerian system, C. Genital tubercle, D. Urachus
A: Urogenital fold
Answer: A: Urogenital fold 
Explanation: Embryologically, the genital tubercule develops into the penis. The edge of the cloacal membrane forms the urogenital fold and by the process of invagination forms the urethral groove and finally the penile urethra. The severity of hypospadias depends on the location of the anomalous opening onto the penile urethra. The mildest degree is where the opening is on the glans and the most severe form at the penoscrotal junction.