A book by Sister Margaret Farley, the Irish American nun who is a member of the Sisters of Mercy religious order and the emeritus professor of Christian ethics at Yale Divinity School, poses a 'grave' risk to other Catholics the Vatican announced this week.

On Monday Vatican authorities strongly criticized Sister Farley for her book on sexuality, claiming that it contradicted church teaching on issues like masturbation, homosexuality and marriage and that its author had a 'defective understanding' of Catholic theology.

The Vatican's slap down came after the publication of Farley's book, 'Just Love: A Framework for Christian Sexual Ethics.'

According to the Boston Herald Pope Benedict approved the decision last March and ordered the decision published. The Vatican said the book 'affirms positions that are in direct contradiction with Catholic teaching in the field of sexual morality.'

In her book Farley writes that masturbation doesn’t raise any moral problems and can actually help relationships rather than hinder them. However the Vatican denied this suggestion and said that according to church teaching 'masturbation is an intrinsically and gravely disordered action.'

The Congregation for the Doctrine of the Faith, the Vatican office tasked with enforcing doctrinal orthodoxy, said that in Farley's book she either ignored church teaching on the core issues of human sexuality or treated it as simply one opinion among many.

But according to the Boston Herald Farley clarified on Monday that she never intended the book to reflect official Catholic teaching. Rather she wrote it to explore sexuality via various religious traditions, theological resources and human experience she said.

The sharp critique of Farley's book was signed by the American head of the congregation Cardinal William Levada, and it comes on the heels of the Vatican’s recent crackdown on the Leadership Conference of Women Religious, accusing it of undermining church teaching and imposing certain 'radical feminist themes' that were incompatible with Catholicism.

In order to silence the nuns the church has now ordered a full-scale examination of the group and its aims and it has appointed three bishops to carry out the task.

But critics contend the Vatican's heavy handed treatment of Sister Farley, a highly regarded American theologian, will further fan the flames of resentment directed at Rome among American nuns groups.

The Vatican's examination of the book first began in 2010. To begin with church authorities sought Farley's responses to its concerns. However when her replies failed to satisfy the Congregation, they moved on to a full-fledged 'examination' that concluded on December 14, 2011.

Another passage that caused the church concern was when Farley wrote that homosexual people and their sex lives should be respected. Current church teaching holds that gays should be respected but that homosexual acts are 'intrinsically disordered.'

On gay marriage, Farley asserted that legal recognition of gay marriage can help transform the stigmatization of gays, a position that Cardinal Levada said would signal the approval of 'deviant behavior' and would obscure the value of traditional marriage between man and woman in society.

In her statement, Farley freely acknowledged that her views on some issues depart from traditional Catholic doctrine, but she said they were nonetheless coherent in theological and moral traditions.

"'The fact that Christians and others have achieved new knowledge and deeper understanding of human embodiment and sexuality seems to require that we at least examine the possibility of development in sexual ethics,' she wrote.