By Christopher Landau
The crisis over child sex abuse in the Roman Catholic Church has cost the organisation both in terms of levels of public trust and compensation payouts.
Campaigners say nuns are too slow to tackle the issue of sex abuse
When American bishops decided in 2002 to conduct an audit of the scale of the problem, their initiative was given a cautious welcome by survivors of sexual abuse.
But one part of the church was not part of the audit.
Nuns, officially known as "women religious", do not always fall under the authority of their local bishop.
This meant they stood outside the remit of the study, even though there are documented cases where Catholic nuns have committed child sexual abuse.
In Portland, Oregon, there are six new lawsuits against the Catholic Church. Two are in relation to accusations made against nuns.
US bishops have a zero tolerance policy on sex abuse by priests
Kelly Clark is a lawyer who specialises in sexual abuse cases in the state.
He said: "I have more resistance these days from religious orders involving nuns, more denial, than I have from any archdiocese or any religious order involving priests."
He says that nuns are 10 to 15 years behind the rest of the church in their attitude to dealing with accusations of abuse.
One campaigner who agrees is Steve Theisen. He was abused over a three-year period by a nun who was a teacher at his school.
His view is: "I don't think they've even taken a first step on this."
Mr Theisen now runs a network for those who have been abused by Catholic leaders.
His research has uncovered more than 60 cases of abuse committed by nuns.
The Leadership Conference for Women Religious is the umbrella group for women's religious orders in the US.
Its executive director, Sister Carole Shinnick, says that her members have worked hard to make sure there are proper policies in place to ensure the protection of children.
But she admits that, unlike the steps taken by bishops to establish the scale of the abuse problem among priests, no audit has been carried out to determine how many nuns have abused children.
"We haven't done an audit... but the fact of the matter is it isn't something we've been asked to do," she said.
And knowing the scale of the problem does not necessarily lead to a solution.
The bishops in the US have now adopted a "zero tolerance" strategy to sexual abuse, which means that priests found to have acted inappropriately must leave the church.
In Silver Spring, Maryland, the St Luke Institute exists to help priests and nuns with psychological problems, including sexual disorders.
The institute was once a major centre for the treatment of priests who had been found guilty of sexually abusing children.
But as a result of the zero tolerance policy, such priests no longer tend to receive treatment within the church - they are simply expelled from the priesthood.
As the director of the centre, the Rev Stephen Rossetti, explains: "Once we throw them out of the priesthood we no longer have a supervisory role - they're gone from our structure.
"They can still be members of the church but they're unsupervised... but where do they go?"
Few would suggest that the scale of the sex abuse problem among nuns will ever reach the rate seen among abusive priests.
But the lessons for the church - about the value of transparency - are the same, and victims of abuse by nuns believe the church has a long way to go to reassure them.