Researchers commissioned by the nation's Roman Catholic bishops to analyze patterns of clergy sex abuse over decades have concluded that homosexuality, celibacy and an all-male priesthood did not cause the scandal.

The report from the John Jay College of Criminal Justice said the majority of molestation cases involved priests who were ordained in the 1940s and 1950s, at a time when seminaries did not properly train them to live a celibate life. These men were not equipped to withstand the social upheaval of the 1960s, which was a time of an increase in sexual deviancy and crime in society at large, the authors said.

The study is the last of three reports the bishops commissioned in 2002, as part of child protection reforms adopted at the height of the abuse crisis. The goal of this latest report was to help identify patterns of abuse and how the church responded to the problem in the hope of better protecting children. The report is to be released Wednesday by the U.S. Conference of Catholic Bishops.

Researchers reviewed abuse allegations from more than 10,000 people against thousands of priests since the 1950s.

The report says the abuse problem peaked in the 1970s, then began declining sharply, at a time when there were no changes in the celibacy mandate and only men were ordained. Therefore, these were not factors in the crisis, researchers said. The majority of known victims were boys, prompting many in the church to say that gay priests were to blame. The John Jay researchers rejected that argument, saying the offenders chose boys because clergy had greater access to them.

According to the report, only a tiny percentage of accused priests _ less than 5 percent _ could be technically defined as pedophiles. The authors of the study define pedophile as an adult with an intense sexual attraction to prepubescent children.

Victim advocates have said that the study cannot be trusted since the raw data was provided by the bishops. A spokeswoman for the bishops' conference insisted the bishops fully cooperated with the study, which was partly funded with a grant from the U.S. Department of Justice.