"If representatives of the Church, who should be the great protectors of the sacred rights of the individual and of the family, act in a totalitarian way (and thereby exhibit the worst type of clericalism), it is simply treason, a denial of the spirit of the Church and of the spirit of Christ. It is a complete abdication in front of the spirit of the world.
"Our clear duty as Catholics is to resist this totalitarian enslavement and, above all, to protect the souls of our children from the damage which threatens them. If the response to the triumph of impurity, the shamelessness, and the barbaric murder of modesty in our epoch is to introduce in Catholic schools this alleged sex education, then let us protest with every available means. Let us fight relentlessly all the Catholic schools which introduce such practices. Not one penny should be given to a pastor who tolerates or endorses this abomination.
"I am no friend of picketing, and I thoroughly dislike this kind of demonstration. But when so grave a question as the souls of our children is at stake, then demonstrations are legitimate and even necessary. We must ceaselessly inundate the bishops with protests, so that if - which, may God forbid! - we do not succeed in opening their eyes to the abomination of sex education, they will at least yield to the pressure exerted by truly Catholic parents. I mean those parents who are the glory and strength of the Church, who believes firmly the Credo of Pope Paul VI, who believe in the infallibility of the Church in matters of faith and morals, and who, unlike the small but noisy group of avant-gardists, accept obediently and lovingly the teaching of Humanae Vitae. It is these quiet millions whose parental rights are being usurped. It is their children whose souls are endangered."
(von Hildebrand, Sex Education: The Basic Issues; 1969, p. 24)