Traditionalist bishops voiced dissent Wednesday after the Episcopal Church became the biggest faith group in the United States to approve a provisional rite for blessing same-sex unions. In a statement, the bishops said the new liturgy -- approved Tuesday at a meeting of the Church\'s governing General Convention in Indianapolis, Indiana -- amounts to same-sex marriage \"for all practical purposes.\" \"It includes all of the essential elements found in a marriage rite: vows, an exchange of rings, a pronouncement and a blessing,\" said the bishops from as far afield as Texas, North Dakota and the New York state capital Albany. \"We believe that the rite subverts the teaching of the Book of Common Prayer, places the Episcopal Church outside the mainstream of Christian faith and practice, and creates further distance between this Church and the Anglican Communion along with other Christian churches.\" They recalled that the worldwide Anglican Communion has repeatedly asked its American branch -- which controversially elected its first openly gay bishop, Gene Robinson, in 2003 -- not to proceed with same-sex rites. Church law still defines marriage as a union between a man and a woman, and there are no plans afoot to change that. Billed by the 1.9 million-member Church as a \"work in progress,\" the same-sex rite is due to go into use from December 2, in dioceses that agree to implement it. It will come under review when the Church\'s General Convention meets in 2015. \"For some people, it\'s going to be troubling. For others, it\'s going to be thrilling,\" Bishop Charles Bennison of Pennsylvania told The Philadelphia Inquirer newspaper prior to the Indianapolis meeting. In their statement, read aloud at this year\'s General Convention that ends Thursday, the dissenting bishops said they remain committed to the spiritual needs of gay and lesbian Church members. But they insisted: \"We believe that the scriptures clearly teach that God\'s vision for sexual intimacy is that it be exercised only within the context of marriage between a man and a woman.\" Jeff Walton, who monitors the Anglican Communion for the Institute on Religion and Democracy think-tank in Washington, told AFP that more bishops were expected to join their dissenting peers. \"They believe it is theologically an error,\" he said, adding that the same-sex rite could prompt many Church-goers to find other places of worship with more traditional values. \"We have (already) seen a lot of individuals voting with their feet\" and going to Evangelical and Roman Catholic churches as well as the upstart conservative Anglican Church in North America, he said. From 2000 to 2010, Walton said, the Church has lost 16 percent of its membership and 23 percent of its average Sunday attendance. Some within the Church leadership advocated an open-arms policy toward to gays and lesbians to help woo newmembers, added Walton in a telephone interview from the General Convention in Indianapolis. Yet overall membership has fallen from 3.5 million in 1965, as the Church scaled back its traditional missionary work and Episcopalian families bore fewer children who could take the pew places of dying elderly members. Earlier this year, Barack Obama became the first serving US president to come out in favor of marriage equality, but homosexuality remains a hot-button issue for both the Roman Catholic and mainline Protestant churches. On Monday, the General Assembly of the Presbyterian Church (USA) voted 338-308 in Pittsburgh against changing its definition of marriage from \"the union of a man and a woman\" to \"the union of two people.\" In May, the General Conference of the United Methodist Church rejected a proposal declaring homosexuality \"incompatible with Christian teaching,\" but at the same time it did not vote on proposals to allow openly gay clergy or same-sex blessings. Only one major Protestant denomination in the United States, the million-member United Church of Christ, has endorsed same-sex marriage outright.