Pope Paul VI stunned the world on July 29, 1968, when he reaffirmed the church’s ban on modern contraceptives in Humanae Vitae (Of Human Life). He declared that “each and every marital act must of necessity retain its intrinsic relationship to the procreation of human life.”

The pope had deferred to a dissenting minority report prepared by four conservative theologian priests on the commission that maintained contraception was a “sin against nature” and a “shameful and intrinsically vicious act.” These theologians said that church could not change its teaching on birth control because admitting the church had been wrong about the issue for centuries would raise questions about the moral authority of the pope, especially on matters of sexuality, and the belief that the Holy Spirit guided his pronouncements. “The Church cannot change her answer because this answer is true. — It is true because the Catholic Church, instituted by Christ — could not have so wrongly erred during all those centuries of its history,” they wrote.

As one of the conservative theologians famously asked one of the female members of the commission, what would happen to “the millions we have sent to hell” for using contraception if the teaching were suddenly changed?