This is confirmed in Srimad-Bhagavatam when Narada speaks of the different symptoms characterizing the four divisions of social life. Narada summarizes that brahmanas, ksatriyas, vaisyas and sudras should be selected by their individual qualifications: Revision history
Diff selection: Mark the radio buttons of the revisions to compare and hit enter or the button at the bottom.
Legend: (cur) = difference with latest revision, (prev) = difference with preceding revision, m = minor edit.