Senator Rob Portman of Ohio announced Friday that he has changed his stance on gay marriage because his son Will is gay. His reversal is being applauded by some Christian LGBT advocates.

Portman now becomes the only sitting Republican to back same-sex marriage, a controversial issue that will be taken up by the Supreme Court at the end of this month.

In an op-ed Friday for Columbus Dispatch on Friday, the Ohio senator explained how he arrived at his new stance and the role his Christian faith played in the reversal. Portman has previously voted against same-sex marriage and gay adoptions.

"I have come to believe that if two people are prepared to make a lifetime commitment to love and care for each other in good times and in bad, the government shouldn't deny them the opportunity to get married," Portman wrote in the Dispatch column.

His reversal on the same-sex marriage issue was instigated two years ago, when his son Will, a junior at Yale, revealed that he was gay.

"At the time, my position on marriage for same-sex couples was rooted in my faith tradition that marriage is a sacred bond between a man and a woman," said Portman. However, as a father of three, he wanted all his children to lead "happy, meaningful lives with the people they love."

"I wrestled with how to reconcile my Christian faith with my desire for Will to have the same opportunities to pursue happiness and fulfillment as his brother and sister," explained Portman. "Ultimately, it came down to the Bible's overarching themes of love and compassion and my belief that we are all children of God."

United Church of Christ LGBT advocates praised Portman's declaration to support marriage equality.

"I'm proud of Sen. Rob Portman who announced his support for the freedom to marry," said the Rev. Mike Schuenemeyer, the UCC's executive and minister for LGBT concerns. "It is a courageous stand in this political climate and another sign of the tide that continues to turn for marriage equality.

"Sen. Portman gave witness to the significance of relationships by stating that his son, who is gay, should be able to enjoy the freedom to marry," Schuenemeyer added. "He is right, and I hope Sen. Portman will join us in Ohio and across the country to make sure everyone has the freedom to marry the person they love."

The UCC passed a resolution affirming equal marriage rights for all couples, regardless of gender, at its 2005 biennial General Synod. The denomination of 1.1 million is a member of the National Council of Churches USA..

While Portman cited his Christian faith for influencing his views on gay marriage, he said religious should be respected and that religious institutions shouldn't be forced to perform weddings or recognize marriages they don't approve of.

The Ohio senator's reversal comes about two weeks before the U.S. Supreme Court is set to hear a challenge against the 1996 Defense of Marriage Act, which defines marriage as between a man and a woman and says states do not have to recognize gay marriages in other states.

Portman, who voted in favor of DOMA while a member of the House of Representatives, indicated that same-sex marriage is a states issue, not one for the Court to tackle.

"The process of citizens persuading fellow citizens is how consensus is built and enduring change is forged. That's why I believe change should come about through the democratic process in the states," wrote Portman in his opinion piece. "An expansive court ruling would run the risk of deepening divisions rather than resolving them."

Thirty states have adopted Defense of Marriage Act, while nine states and Washington D.C., have legalized gay marriage.