U.S. President Barack Obama has for the first time publicly expressed support for same-sex marriage on Wednesday, citing his Christian faith's "Golden Rule" as a factor, while the head of the gay-marriage-affirming denomination to which the President once belonged called the stance courageous.

Obama, who had previously signed into law a measure that allowed gays and lesbians to serve in the military had previously stopped short of endorsing same-sex marriage. Throughout his presidency he has said his views on the matter had been "evolving."

In his comments in a televised interview on Wednesday Obama said the principle of treating others the way one would want to be treated guided his decision, even though he acknowledged some fellow Christians would not agree with him.

"I'd hesitated on gay marriage in part because I thought civil unions would be sufficient," he said in an interview with ABC News. "And I was sensitive to the fact that for a lot of people the word 'marriage' was something that invokes very powerful traditions, religious beliefs, and so forth."

The issue of same-sex marriage has been a heated topic of debate within U.S. denominations. Last week, the United Methodist Church's top court ruled that a policy adopted at a regional conference in New York allowing clergy "to marry at their own discretion" is "neither valid nor constitutional."

Other mainline denominations, including the United Methodist Church, the Evangelical Lutheran Church in America, the Presbyterian Church (USA) and the Episcopal Church, do not approve of same-sex marriages.

Obama said that he and his wife's Christian faith is behind his support.

"In the end the values that I care most deeply about and she cares most deeply about is how we treat other people," he said. "We are both practicing Christians and obviously this position may be considered to put us at odds with the views of others but, you know, when we think about our faith, the thing at root that we think about is, not only Christ sacrificing Himself on our behalf, but it's also the Golden Rule-treat others the way you would want to be treated."

"And I think that's what we try to impart to our kids and that's what motivates me as president, and I figure the most consistent I can be in being true to those precepts, the better I'll be as a dad and a husband and hopefully the better I'll be as president," he added.

A leader from the United Church of Christ, a denomination which included the President's former church in Chicago, applauded the news. The UCC, with just over 1 million members is the 23rd largest church in the U.S., according to the National Council of Churches' 2010 Yearbook.

"I am pleased to hear that President Obama, a member of the United Church of Christ for more than 20 years, has affirmed his support for marriage equality," said the Rev. Geoffrey A. Black, general minister and president of the UCC. "I applaud his important and courageous stance."

The Rev. Dr. C. Welton Gaddy, president of Interfaith Alliance called the President's comments "historic" but expressed the U.S. Constitution, not his faith needed to guide policy going forward.

"President Obama's affirmation of the right to same gender marriage today is an important and historic moment in the life of the nation. His statement shows that he understands his role is to protect Constitutional principles over sectarian ideology," he said.

"While I appreciate that the president thinks his position is consistent with his faith – a belief I have long held – it is the Constitution, not his religion that should form the basis of his position," he added.

"The continued denial of equality to the LGBT community is an anachronism in today's world. I hope and trust that the President will now lead us down a path towards public policy that codifies the right to marriage equality for the LGBT community."

Issues relating to same-sex marriage have been in the political spotlight during the last week, as North Carolina voters passed a measure on Tuesday defining marriage as an institution between a man and a woman, and recently Obama administration officials Vice President Joe Biden and Education Secretary Arne Duncan expressed support for same-sex marriage.

In 2009, ELCA opened the ministry of the church to gay and lesbian pastors and other professional workers living in committed relationships but did not use the word "marriage."

The Episcopal Church, which allows openly gay clergy to serve, is set to consider a proposal later this year that would institute rites to bless same-gender relationships. The Presbyterian Church (USA) currently allows gay and lesbians to serve as clergy members.

The United Methodist Church currently states homosexuality is incompatible with Christian teaching and disallows both openly gay clergy and ceremonies celebrating gay unions. Delegates of the church's top lawmaking body rejected a resolution last week that would have officially stated that views on homosexuality are conflicted within the church.

The president of the nation's largest non-Catholic denomination, the Southern Baptist Convention, said the development was "depressing."

"It is very depressing news when the president of the United States uses his power of influence to endorse same-sex marriage," Wright, pastor of Johnson Ferry Baptist Church in Marietta, Ga., told the Baptist Press. "... Scripture is very clear that from the beginning, God intended marriage to be between one man and one woman. It is important for us who are followers of Jesus to uphold the sacredness of marriage according to Scripture."

Under Obama's guidance, his Administration has decided not to defend the Defense of Marriage Act, a federal law which defines marriage as the legal union of one man and one woman. The law states no state is required to recognize a same-sex relationship considered marriage in another state.