<prompt> Adult leydig cells are originated fromFetal leydig cellsUndifferentiated progenitor cells which appear in testis before bihUndifferentiated progenitor cells which appear in testis after bihAll of the above  <response>: 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 