ROME — Pope Francis celebrated families Saturday and urged them to shun “selfish” decisions that are indifferent to life as he closed out a big Vatican rally a day after the U.S. Supreme Court ended constitutional protections for abortion.

Francis didn’t refer to the ruling or explicitly mention abortion in his homily. But he used the buzzwords he has throughout his papacy about the need to defend families and to condemn a “culture of waste” that he believes is behind the societal acceptance of abortion.

“Let us not allow the family to be poisoned by the toxins of selfishness, individualism, today’s culture of indifference and waste, and as a result lose its very DNA, which is the spirit of welcoming and service,” he said.

The pope, noting that some couples allow their fears and anxieties to “thwart the desire to bring new lives in the world,” called for them not to cling to selfish desires.

“You have been asked to not have other priorities, not to ‘look back’ to miss your former life, your former freedom, with its deceptive illusions,” he said.

Francis has strongly upheld church teaching opposing abortion, equating it to “hiring a hitman to solve a problem.” At the same time, he has expressed sympathy for women who had abortions and made it easier for them to be absolved of the sin of undergoing the procedure.

The Catholic Church holds that life begins at conception and must be protected and defended until natural death.

Francis delivered his homily in a packed St. Peter’s Square at the end of the World Meeting of Families, a four-day conference held every few years aimed at helping church workers provide better pastoral care for families, especially those in difficulty.

The Vatican welcomed Friday’s ruling overturning Roe v. Wade, the 1973 decision that provided constitutional protections for abortion in the U.S.

The Holy See’s main bioethics body, the Pontifical Academy for Life, said it “challenges the whole world” to reopen debate about the need to protect life.

Abortion is legal in Italy and most of Europe.