The policy is outlined in a guide for lay leaders known as Handbook 1, parts of which were posted online by a popular Mormon podcaster who was excommunicated by the church earlier this year on grounds that his public dissents drove others away from the Church of Jesus Christ of Latter-day Saints
, the Mormon church's official name.
In a statement, a Mormon church spokesman, Eric Hawkins, described the document as a "policy and procedural guide" and reaffirmed the church's longstanding opposition to same-sex marriage.
"While it respects the law of the land, and acknowledges the right of others to think and act differently, it does not perform or accept same-sex marriage within its membership," the statement said.
John Dehlin, the excommunicated founder of the podcast "Mormon Stories" and a self-described "unorthodox" Mormon, posted the documents detailing the changes on Facebook Thursday
, saying "legally married LGBT Mormons" will likely be "hunted down and threatened with the inhumane and barbaric" church disciplinary procedures.
"We are all diminished by this unfortunate action," Dehlin wrote. "As the LDS church continues to paint itself into a corner, it risks becoming increasingly irrelevant to the developed world."
Troy Williams, executive director of Equality Utah, which pushed for Utah's law protecting the LGBT community and religious freedom, said in a statement said that all churches have the "religious liberty to welcome or exclude whomever they desire."
"But we know that children of same-sex parents are treasures of infinite worth," he said. "In our universe, all God's children have a place in the choir."
Scott Fausett -- who is gay and has three children, including one in the LDS priesthood -- told CNN affiliate KUTV
that he was unsure how the change will affect his family.
"It is one thing if the LDS Church doesn't want me being a gay person in their church -- now to exclude children of a gay person just makes no sense to me," Fausett told the station.
Under the new policy, the Mormon church will forbid the "natural or adopted" children of parents in same-sex relationships from receiving a name and a blessing in a ceremony performed by the Mormon priesthood, according to the handbook.
Additionally, children of same-sex unions will be required to be of legal age and no longer living with their parents in order to be baptized, confirmed, ordained or recommended for missionary service. Under the policy, the child would also have to disavow same-sex relationships.
Baptism and confirmation would also require the approval of the church's governing First Presidency, according to the handbook.
Handbook 1 also expands the meaning of apostasy to include members who "are in a same-gender marriage."
The Mormon church, like other religious groups, has tried to strike a delicate balance on gay rights.
Mormons have fought the legalization of same-sex marriage, for example, while trying to avoid the "anti-gay" label sometimes affixed to conservative faiths. Many church members were particularly stung by the fierce backlash to Prop 8. The Mormon-backed referendum was later struck down in court.
Nearly two-thirds of Mormons say homosexuality should be discouraged by society, according to a 2012 survey conducted by the Pew Forum on Religion & Public Life. The church's official position is that same-sex attraction is not a sin, but acting on it is.
At the same time, Mormon leaders have taken an increasingly civil tone towards gays and lesbians in recent years, and gay rights groups cheered the church for endorsing the Boy Scouts' decision to allow gay scouts in 2013.
With nearly 6.5 million members in the United States, the Mormon church is one of the largest in this country to offer support of LGBT anti-discrimination laws, second only to the United Methodist Church.
The country's two largest Christian denominations, the Catholic church and Southern Baptist Convention, have opposed the Employee Non-Discrimination Act, or ENDA. None of those groups condone gay marriage.