Five hundred years from now ---- if the human race has not erased itself line by line and gene by gene, has not replaced itself with some race of Orcs, half-chimp and half-machine --- people will way that the turning point in our preservation as a species was the publication of Humanae Vitae in 1968.
Paul VI was thought a weak, Hamlet-like, vacillating pope. But he was a prophet: for those who have ears to hear.