WASHINGTON — The sexual abuse crisis in the Catholic Church was caused by the influence of sweeping social changes and increasing “deviant behavior’’ of the 1960s and 1970s on priests who were inadequately trained, emotionally unprepared, and isolated, according to a new report commissioned by the nation’s Roman Catholic bishops.

Researchers at John Jay College of Criminal Justice at the City University of New York, who spent five years conducting the most expensive and extensive study of sexual abuse in the Catholic church to date, concluded that homosexual priests were no more likely to abuse than heterosexual priests.

They also found that celibacy could not be blamed for the abuse epidemic. Nor could seminaries have done a better job screening for likely offenders because abusive priests had no common profile.

Wrote the authors: “The most significant conclusion drawn from this data is that no single psychological, developmental, or behavioral characteristic differentiated priests who abused minors from those who did not.’’

The report also states that poor training of priests, combined with social isolation, job stress, and few support mechanisms likely contributed to the abuse problem. The decline of sexual abuse in the mid-1980s coincided with better training for seminarians in human sexuality and relationships.

The report, titled “The Causes and Context of Sexual Abuse of Minors by Catholic Priests in the United States, 1950-2010,’’ appears to deflect most blame for the crisis away from the church. However, the study acknowledges that there was little evidence before 2002 “that diocesan leaders met directly with victims.’’ Instead, church leaders focused on the abusive priests rather than on their victims.

Abusive priests have often been branded pedophiles, but the report — in a declaration that appears destined to stir controversy — insists that fewer than 5 percent actually met that definition. In the process, however, the study’s authors seem to redefine what constitutes pedophilia.

Major associations of psychiatrists typically define pedophilia as interest in children 13 and younger, calling them “prepubescent.’’

But to reach their conclusion about the low incidence of the disorder among priests, the report authors seem to suggest that the prepubescent period ends at age 10.

“The majority of victims were pubescent or postpubescent,’’ the report states. “Thus,’’ they wrote, “it is inaccurate to refer to abusers as pedophile priests.’’

The researchers called the sexual abuse scandal, which began unfolding in Boston in 2002, a “historical problem.’’ They said reports of abuse rose sharply in the mid-1960s, peaked in the late 1970s, and declined in the 1980s, mirroring the trend in society generally.

The report also states that “the documented rise in cases of abuse in the 1960s and 1970s is similar to the rise in other types of “deviant’’ behavior in society, and coincides with social change during this time period.’’

The study, which cost about $2 million, about half of which was paid for by the church, was to be released today by the US Conference of Catholic Bishops, but the Religion News Service first reported its findings on its website last night. The Globe also obtained a copy of the report last night.

The study met with quick criticism, however.

“The study seems to focus on the offending priests in a way that minimizes the gravity of their crimes, and gives short shrift to the ‘other crime’ — the enabling, concealing, and fostering of abuse by the US bishops and the Vatican bureaucracy,’’ said Terence McKiernan of BishopAccountability.org, in a statement on news reports concerning the leaked study last night.

“The report also grotesquely emphasizes the ‘vulnerability’ of the priests who committed the crimes, and neglects the defenseless children who suffered them. In these respects, the first Causes and Context report — the Bennett Report of 2004 — was a better report than its successor.’’

Lisa Wangsness can be reached at lwangsness@globe.com.

© Copyright 2011 Globe Newspaper Company.