By Tom Heneghan, Religion Editor

PARIS (Reuters)- A German Catholic Church study showed most priests found guilty of sexually abusing minors were psychologically normal, according to survey results presented on Friday.

Only 12 percent of those surveyed were diagnosed as paedophiles, said the report released by Trier Bishop Stephan Ackermann, the church's spokesman on abuse cases.

Psychological tests commissioned by priests' dioceses around Germany found only five percent could be classified as ephebophiles - attracted to teenagers, it said.

"There are no significant differences to results found in the general population in Germany," said Dr Norbert Leygraf, one of the experts reviewing reports on predator priests found out in the past decade.

Victims advocate Norbert Denef dismissed the study as biased in favor of the Church that commissioned it, and called for an independent commission to study clerical abuse cases.

"You wouldn't ask the mafia to investigate its own crimes," Denef, head of an advocacy group called Netzwerk B, told daily newspaper Die Welt.

A wave of revelations of clerical sexual abuse, with many cases dating from previous decades, shook the German Catholic Church in 2010 and prompted it to order an overall study of diocesan reports to spot any trends.

MOST VICTIMS MALE

About 600 people filed accusations of sexual abuse against priests following these revelations. Some 180,000 Germans left the church that year, a 40 percent jump over 2009.

Leygraf gave no reason why so many men described as psychologically normal, 68 percent of the group under investigation, had abused minors.

"The alleged sexual abuse was committed for reasons that can mostly be described as within normal psychological bounds and only a few cases resulted from a specific psychopathology," he said, according to a Church statement.

According to the study, the diocesan reports showed 54 percent of the priests were identified as heterosexual, 37 percent as homosexual and nine percent as bisexual.

Ackermann ruled out any link to celibacy, a rule for Catholic priests that some critics blame for the wave of abuse cases that have rocked Catholic communities in Europe and North America for over a decade.

"There is no causal connection between a celibate way of life and sexual abuse," he told a news conference in Trier.

Almost all the priests said they met their victims in their parishes or in schools. Asked why three-quarters of victims were male, Ackermann noted many cases dated back several decades when priests were likely to only come into contacts with boys.

"There were no girl altar servers back then," he said. "The boys were there and were the ones the priests had the most to do with in their daily work."

(Editing by Louise Ireland)