Pope Francis had strong words for couples who choose not to have children, saying Tuesday that their self-imposed infertility was at the root of the demographic winter plaguing the West.

“Think of how all of us are continually urged to live in a comfortable and greedy individualism, only concerned with our own well-being, our free time and our self-fulfillment,” the pope told a group of Catholic students at Rome’s Cathedral of Saint John Lateran.

This relates directly he said, to “an issue that makes me suffer: our demographic winter.”

“‘But why don’t you have at least one child, or two?’” – the pontiff dramatized. “‘No, I think I’d like to wait a little longer, maybe take a trip…’ And so, couples go on in barrenness, out of selfishness, looking to have more, even to make cultural journeys, but without children. That tree bears no fruit.”

While the pope has insisted that Catholic couples do not have to multiply “like rabbits,” he has also urged them to have children, decrying the demographic winter that is felt so acutely in Europe, with its birthrate well below replacement levels.

“Just think of many of the societies we know here in Europe,” Francis said in February 2015. “They are depressed societies, because they don’t want children, they don’t have children, and the birthrate doesn’t even make it to one percent.”

The pope continued on this theme in his address Tuesday, saying that this aversion to having children was the fruit of self-centeredness.

“The demographic winter that we all suffer from today is the effect of this selfish groupthink, concerned only with self, seeking only ‘my’ fulfillment,” he said. “You students should think hard about this: think about how ‘savage’ this groupthink is. It seems very ‘cultural’ but it is ‘savage,’ because it prevents you from making history, from leaving a legacy behind you.”

“How dangerous this all is, how it separates us from others and therefore from reality, how it makes us sick and delirious! The many neuroses…,” he said. “It often turns quickly into the exaltation of one’s personal or group ‘ego,’ in contempt and dismissal of others, of the poor, in a refusal to be challenged by the evident destruction of creation! This is a disgrace!”

In closing, the pope said that the only cure for the selfishness that causes barrenness is the self-giving and generosity that Jesus inspires in the gospel.

“You understand well that the gospel gives us the deepest and most radical antidotes to defend ourselves and heal from the disease of individualism,” he said.

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