The dean of Yale Divinity School, Harold W. Attridge, a Catholic layman, and the president of the Sisters of Mercy, Sister Patricia McDermott, issued statements in support of Sister Farley. So did 15 fellow scholars who, in a document released by the divinity school, testified to Sister Farley’s Catholic credentials and the influence she has had in the field of moral theology.

Cardinal Levada’s statement about the book, dated March 30 but released on Monday, said that it “cannot be used as a valid expression of Catholic teaching, either in counseling and formation, or in ecumenical and interreligious dialogue.” Pope Benedict XVI approved the statement’s contents and ordered its publication, it said. The statement comes as the Vatican struggles to contain a controversy over leaked documents that showed infighting and mismanagement in the papacy of Benedict XVI, who on Sunday concluded a three-day meeting in Milan to promote family values.

The Vatican spokesman, the Rev. Federico Lombardi, said the Vatican had not called for any sanctions against Sister Farley and was not expected to do so because she has retired from teaching.

Sister Farley’s book finds moral and theological justifications for same-sex marriage, which aside from abortion, has become the major galvanizing political and moral issue for American bishops. The statement took Sister Farley to task for writing that same-sex marriage “can also be important in transforming the hatred, rejection, and stigmatization of gays and lesbians.” She wrote that “same-sex relationships and activities can be justified according to the same sexual ethic as heterosexual relationships and activities.”

“This opinion is not acceptable,” the Vatican statement said. The Catechism of the Catholic Church, it said, says homosexual acts are “acts of grave depravity” that are “intrinsically disordered” and “contrary to the natural law.” It said that Sister Farley’s assertion that sometimes divorce is a reasonable option for couples who have grown apart contradicted church teaching on the “indissolubility of marriage.”

The statement quoted liberally from some of the racier passages in “Just Love,” including ones in which Sister Farley writes that female masturbation “usually does not raise any moral questions at all.” She adds that “many women” have found “great good in self-pleasuring — perhaps especially in the discovery of their own possibilities for pleasure — something many had not experienced or even known about in their ordinary sexual relations with husbands or lovers.”

The Vatican said this assessment contradicted church teaching that “the deliberate use of the sexual faculty, for whatever reason, outside of marriage is essentially contrary to its purpose.”