From Manu, one son became a ksatriya, another a brahmana, and another a vaisya. This confirms the statement by Narada Muni, yasya yal laksanam proktam pumso varnabhivyanjakam (Bhag. 7.11.35). One should always remember that brahmanas, ksatriyas and vaisyas should never be regarded as members of a caste by birth. A brahmana may be changed into a ksatriya, and a ksatriya into a brahmana. Similarly, a brahmana or ksatriya may be changed into a vaisya, and a vaisya into a brahmana or ksatriya. This is confirmed in Bhagavad-gita (catur-varnyam maya srstam guna-karma-vibhagasah [Bg. 4.13]). So one is a brahmana, ksatriya or vaisya never by birth, but by quality. There is a great need of brahmanas. Therefore, in the Krsna consciousness movement, we are trying to train some brahmanas to guide human society. Because at present there is a scarcity of brahmanas, the brain of human society is lost. Because practically everyone is a sudra, no one at the present moment can guide the members of society to the proper path by which to achieve perfection in life.