''An enormous number of priests struggle with celibacy,'' Philip O'Donnell told the state inquiry into how the churches handle child sex abuse.
''There's a tolerance for imperfection in celibacy, and that may have led to a lessening of outrage at sex with children.''
He said he had no training about celibacy in the seminary and that many priests were ill-equipped. ''Chosen celibacy is a gift, but mandatory celibacy is for many priests a millstone,'' he said.
Mr O'Donnell declined to speculate on what percentage of Catholic priests, who must vow to be celibate, were sexually active, but another Melbourne priest has separately suggested it is about half.
Asked by committee member Andrea Coote whether priests believed only sex with women counted as real sex (breaking celibacy vows), and that homosexual and child sex did not, Mr O'Donnell said: ''Sometimes.''
He said another priest told him the celibacy requirement would never change because so many priests were gay and it was ''great cover. No one asks me why I am 50 and single - they assume I am celibate,'' the priest told Mr O'Donnell.