Pope Benedict has expressed surprise at the sharp decline in regular attendance at Mass in Ireland, particularly among younger people.
Speaking to The Irish Times the Archbishop of Dublin, Dr Diarmuid Martin, said the Pope was taken aback when he told him about the situation.
The archbishop said that the most dramatic surprise for him on his own return to Dublin three years ago was the degree to which young people had drifted away from active church life.
"I can go to parishes on a Sunday where I find no person in the congregations between the ages of 16 and 36. None at all."
He added: "This has to be looked at in a situation where, anyhow, regular practice in a substantial number of parishes in Dublin is below 5 per cent."
Such regular attendance as existed was more a feature of middle-class Dublin, he said.
"Donnybrook is full compared to comparatively poor parishes," he said. But where young people were concerned it was "a huge challenge".
He remarked on the enthusiasm of so many Irish young people at the World Youth Day events in Cologne last August, which he attended as did Pope Benedict.
Yet, when they came back to Ireland, there was "little to engage them" in parishes.
"It was not a case of hostility to the church on their part, he said, just that they didn't socialise at parish level."
He addressed these issues in an interview in the March edition of Intercom magazine and in his talk at the "Question of Education" seminar in Dublin this week.
The seminar was organised by the Communion and Liberation group and inspired by its founder Luigi Giussani's book The Risk of Education.
At that seminar the archbishop asked: "Where is this missing generation? The challenging message of Jesus Christ has touched the hearts of generations over 20 centuries, what are the factors which seem to alienate the current generation of 15 to 35-year-olds from the church of Jesus Christ?"
He continued: "I meet young people who have spent up to 10 years attending school-based catechetical programmes and yet enter into life with only a very superficial religious culture."
Emphasising that he was not criticising "the extraordinary teachers that we have in our schools", he said "our system of religious education has not produced results proportionate to the investment that has been made".
