Italian Prime Minister Giorgia Meloni also pledges that her government will do everything it can to reverse the rapidly falling birth rate in Italy, but warns the country must not turn to surrogacy as an answer.
"Selfish, egotistical" young Italians should have more children and fewer pets, the Pope has told a conference of pro-family organisations in Rome.
He was speaking with Italian Prime Minister Giorgia Meloni in an effort to urge political leaders to reverse a "demographic winter" in the country, which last year saw a population dip of more than 300,000.
After blasting couples who were choosing to have pets instead of children, the Pope said dedicated resources should be diverted to help them grow families, adding it was necessary to "plant the future" with hope.
"Let us not resign ourselves to sterile dullness and pessimism," Francis told an annual gathering of pro-family organisations in Rome.
"Let us not believe that history is already marked, that nothing can be done to reverse the trend."
Italy had a record low of live births in 2022, at 392,598, which when combined with a high number of registered deaths, at 713,499, has meant the country has accelerated a demographic trend that could impact its social security system.
Ms Meloni, who is considered to be a right wing leader in Italy, and her government, is backing a campaign to encourage at least 500,000 births every year by 2033, which is the rate demographers say is needed to protect the economy from collapse so that more people can work as the rate of pensioners increases.
The premier ran on a pro-family campaign of "God, family, fatherland", with her government proposing several measures to encourage families to have more children.
Italy's fertility rate is among the lowest in the world, at 1.24 children per woman.
A lack of affordable childcare, low pay, and unstable work are among the reasons why many women put off having children.
Ms Meloni, who does have a child with her partner, told the conference she wants to reverse the declining trend of births, but warned surrogacy should be avoided, touching on broader political points around migrants and same-sex couples.
"We want a nation where it is no longer scandalous to say that - whatever the legitimate, free choices, inclinations of each person - we are all born of a man or a woman," Ms Meloni said, to applause.
"Where it is not taboo to say that motherhood is not for sale, that wombs are not for rent and children are not over-the-counter products that you can choose on the shelf as if you were in the supermarket and maybe return if then the product does not match what you expect."
She also spoke in a religious sense, saying her government wants to begin by "respecting the dignity, the uniqueness, the sacredness of every single human being, because each of us has a unique and unrepeatable genetic code. And this, like it or not, has something of the sacred".