Parents do not tell their children facts which they know to be false
Taylor says the following on pages 170-1:
Rabbi Moshe ben Nachman, the Ramban, explains that if the initial parents did not witness first-hand the cataclysmic Sinai event of God speaking and giving instruction to the entire nation, they would never have believed it and would not have collectively passed it on to their children as a fact. It is possible for parents to pass on false ….. ideals that they believe to be true, like Communism for example. However, they will not tell over to their children things as facts that they know to be utterly false.