In regard to the instructions of the father and mother, it may be said that every living entity, including even the insignificant cats, dogs and serpents, takes birth of a father and mother. Therefore, getting a material father and mother is not a problem. In every form of life, birth after birth, the living entity gets a father and mother. In human society, however, if one is satisfied with his material father and mother and their instructions and does not make further progress by accepting a spiritual master and being educated in the sastras, he certainly remains in darkness. The material father and mother are important only if they are interested in educating their son to become free from the clutches of death. As instructed by Rsabhadeva (SB 5.5.18): pita na sa syaj janani na sa syat/ na mocayed yah samupeta-mrtyum. One should not strive to become a mother or father if one cannot save one's dependent son from the impending danger of death. A parent who does not know how to save his son has no value because such fathers and mothers may be had in any form of life, even among the cats, dogs and so on. Only a father and mother who can elevate their son to the spiritual platform are bona fide parents. Therefore according to the Vedic system it is said, janmana jayate sudrah: one is born of a material father and mother as a sudra. The purpose of life, however, is to become a brahmana, a first-class man.
From Srila Prabhupada's purport to SB 6.5.20