The church-commissioned studies also reported that 4400 priests preyed on mostly young boys, sometimes after plying them with drugs and alcohol.
The offenses typically occurred in the priest's home or in the church and involved boys aged 11 to 14, according to the study by John Jay College of Criminal Justice at the City University of New York.
Most of the offenses dated to the 1960s and 1970s, and 80% of them were homosexual in nature.
The other study looking at the causes and context of the scandal said the church was not vigorous enough in screening candidates for holy orders and that many of the priests were ill-prepared to abide by their vows of chastity.
"Firstly dioceses and orders simply did not screen candidates for the priesthood properly,'' Robert Benett, a member of the National Review Panel that carried out the study, said.
"As a result we found many dysfunctional and psycho-sexually immature men were admitted into seminaries and later ordained into the priesthood."
The offenses typically occurred in the priest's home or in the church and involved boys aged 11 to 14.
Its report was critical of the church hierarchy for trying to cover up what it called this "epidemic of abuse."
"Some bishops and other Church leaders often put what they erroneously believed to be the institutional concerns of the local Church above the concerns of the universal Church," the report said.
"The fear of scandal caused them to practice secrecy and concealment."
Bishops allowed known sex offenders to remain in their posts, or reassigned to other parishes within the same diocese "with distressing frequency," and even sent them to other dioceses "where they posed a further threat to children that predictably materialized into additional incidents of abuse."
About 150 sexual offenders who were moved around in this way molested close to 3000 youngsters between them, the Jay report said.