The way the Church views sexual abuse has evolved, just as it has in wider society, the pope said Tuesday, adding events in the past should not be judged with today's eyes.
"It's true that the Church is accused, we all know it, we know the statistics," the pope said in the plane bringing him back from a visit to the Baltic states.
"But if just one priest abuses a child, it's monstruous."
"I understand that young people are outraged by such massive corruption," he said, echoing his speech to youths in Estonia earlier in the day.
"They know that this happens everywhere, but in the Church, it's more outrageous because they're supposed to take children to God, not to destroy them."
The Catholic Church has been rocked by a fresh wave of devastating claims of sexual abuse committed by clergy across the globe.
Scandals in Australia, Europe, and North and South America have involved widespread claims of abuse -- and cover-ups -- by clergymen and lay members with one Vatican archbishop describing it as the church's "own 9/11".
Citing a report released in August about thousands of cases of abuse committed by priests in Pennsylvania, the pope noted the situation has changed greatly since the 1970s.
"In the most recent times, it (abuse) has diminished because the (American) Church realised that it had to fight in a different way."
"In past times, things were hidden. They were also hidden at home, when uncles raped a niece, when the father raped his children. These things were hidden, because it was a great shame."
"That was the way of thinking in past centuries, or in the last century," the pope said, adding that the past should not be judged with today's eyes.
He cited the example of the death penalty, which the Vatican applied until the late 19th century: "Then the moral conscience grows."
But the pope declined to answer a question about a damning report released in Germany on Tuesday showing that almost 3,700 minors -- mostly boys -- were assaulted between 1946 and 2014.
The German Catholic Church apologised for the abuse, saying the perpetrators must be brought to justice.