This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology, Subject name: Medicine
Adult leydig cells are originated from 
Select and explain. 
A. Fetal leydig cells, B. Undifferentiated progenitor cells which appear in testis before bih, C. Undifferentiated progenitor cells which appear in testis after bih, D. All of the above
C: Undifferentiated progenitor cells which appear in testis after bih
Answer: C: Undifferentiated progenitor cells which appear in testis after bih 
Explanation: Fetal Leydig cells atrophy after bih and do not contribute to the origin of adult Leydig cells, which originate from undifferentiated progenitor cells that appear in the testis after bih and acquire full steroidogenic function during pubey. Ref Harrison 20th edi page no 2769