Oedipus' Relation to Evan's Enormous Question

The parents of Oedipus believe that, because their son is prophesized to kill the father and marry his mother, it is justified or OK to wound him and leave him on a hillside for death to take . Most parents would strongly disagree with this rationalization of killing their own child. If two parents believe it is OK, but the rest of the parental population thinks it is terrible and a bad think to do, what is the overall verdict? Are children basically taught what is right from wrong from his or her parents? Or is therre some naturaly instilled values of good and bad? In Oedipus' case, he did not have the chance to require the basic teachings of his parents. Does this jeopodize his view of "good" and "bad"? Killing and incest are basically "bad" things to do today, and were also probably "bad" things to do in the ancient Greek period. Do "bad" and "good" change over time? Tiresias, the blind "seer", acts possibly as a third party when it comes to deciding on a matter. Although Tiresias does not address good and bad he proposes the truth to Oedipus.