INDIANAPOLIS — Episcopalians approved a churchwide ceremony Tuesday to bless same-sex couples, the latest decisive step toward accepting homosexuality by a denomination that nine years ago elected the first openly gay bishop.
At the Episcopal General Convention, which is divided into two voting bodies, about 80 percent of the House of Deputies voted to authorize a provisional rite for same-sex unions for the next three years. A day earlier, the House of Bishops approved the rites 111-41 with three abstentions during the church meeting in Indianapolis.
Supporters of the same-sex blessings insisted it was not a marriage ceremony despite any similarities. Called ‘‘The Witnessing and Blessing of a Lifelong Covenant,’’ the ceremony includes prayers and an exchange of vows and rings. Same-sex couples must complete counseling before having their unions or civil marriages blessed by the church.
Other mainline Protestant churches have struck down barriers to gay ordination in recent years or allowed individual congregations to celebrate gay or lesbian unions. However, only one major US Protestant group, the United Church of Christ, has endorsed same-sex marriage outright.
In a separate vote Monday, the full Episcopal convention approved new antidiscrimination language for transgendered people that cleared the way for transgendered clergy.
‘‘I believe the Episcopal Church will continue to evolve on the issue of marriage equality and look forward to joining our UCC brothers and sisters in being a headlight instead of taillight on marriage equality,’’ said the Rev. Susan Russell, an Episcopal priest and longtime gay advocate in the denomination.
Under the new policy, each Episcopal bishop will decide whether to allow the ceremonies in his or her local diocese.
Six states and the District of Columbia have legalized gay marriage and three more states could do so this year, while 30 states have passed constitutional amendments limiting marriage to unions between a man and a woman.
Episcopalians had already blazed a trail — and caused an uproar — in 2003 by consecrating New Hampshire Bishop Gene Robinson, the first openly gay bishop in the Anglican world.