"This is an important moment for those of us who were raped, sodomised and sexually violated as children by priests," said Barbara Blaine, president of the Survivors Network of those Abused by Priests (SNAP), a global coalition based in the United States.
"Over the years, we've struggled to understand why Church officials continue to support and cover up for sexual predators," Blaine told reporters, two days before the UN Committee on the Rights of the Child was to examine the Vatican's record.
Signatories of the 1989 UN Convention on the Rights of the Child agree to be scrutinised by a watchdog panel.
Thursday marks the Vatican's second examination. Its debut was in 1995, before the abuse of minors by Catholic priests burst into the spotlight.
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For more than a decade, the Church has been rocked by a cascade of scandals from Ireland to the United States and from Australia to Germany.
Victims' groups, however, say the issue is far from settled and that the tally could well be in the hundreds of thousands.
Abuse has often been coupled with cover-ups by priests' superiors, typically transfers to other parishes, rather than turning them over to police.
A 1986 internal Church report on abuse had little or no impact, said Spanish SNAP member Miguel Hurtado.
"When that report was written, I was four years old. When I was abused, I was 16. They had 12 years to try to sort out the problem. They had 12 years to try to implement measures. They had 12 years in which they did absolutely nothing," he said.