The Vatican is being confronted publicly for the first time over the sexual abuse of children by clergy, at a UN hearing in Geneva.
The Church was asked why it continued to describe such abuse as an offense against morals rather than a crime against children.
Archbishop Silvano Tomasi said such crimes could "never be justified" and every child should be "inviolable".
The Vatican earlier refused a request for data on abuse.
When it argued that such cases should be heard in the countries where they took place, it was accused of responding inadequately to abuse allegations.
This is the first time the Holy See is defending itself in public over its record on sex abuse.
Victims say they hope the hearing, which is being broadcast live, will prompt the Church to end its "secrecy".
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Something strange happened and he started putting his hands under my T-shirt and that's when the abuse actually started”
Teodoro Pulvirenti Victim of abuse by a priest
Pope Francis announced last month that a Vatican committee would be set up to fight sexual abuse of children in the Church and offer help to victims. He also broadened the definition of crimes against minors to include sexual abuse of children.
The Holy See is a signatory to the UN Convention on the Rights of the Child, a legally binding instrument which commits it to protecting and nurturing the most vulnerable in society.
It ratified the convention in 1990 but after an implementation report in 1994 it did not submit any progress reports until 2012, following revelations of child sex abuse in Europe and beyond.
It was, Archbishop Tomasi said in his opening statement, important to establish the truth of what had happened in the past, to prevent it ever happening again, to see justice done and to provide healing for the victims.
The Vatican, he told the panel, would welcome any suggestions from the UN's Committee on the Rights of the Child (CRC) to implement its obligations.
CRC members then set out their questions, asking about the Church's practice of moving priests suspected of abuse and allegations that it had concealed such abuse.