Terry Gilbert, left, kisses his husband Paul Beppler after wedding at Seattle City Hall, becoming among the first gay couples to legally wed in the state, Dec. 9, 2012, in Seattle, Washington. (AP Photo)

Terry Gilbert, left, kisses his husband Paul Beppler after wedding at Seattle City Hall, becoming among the first gay couples to legally wed in the state, Dec. 9, 2012, in Seattle, Washington. (AP Photo)

Most Americans now back gay marriage, something that was almost unheard of just one generation ago, and that support is even growing among the most conservative young Americans–evangelical Christians.

Among all Americans, 56 percent favor same-sex marriage while 32 percent remain opposed to it, according to the General Social Survey. An analysis of its findings on gay marriage was conducted by The Associated Press-NORC Center for Public Affairs Research and the General Social Survey.

Among white evangelical Protestants, 28 percent favor gay marriage while 66 percent oppose it. However, when you look at young evangelicals–those aged 18 to 34–43 percent support same-sex unions while 54 oppose it, according to the Public Religion Research Institute.

These more tolerant attitudes toward gay marriage are driven by social relationships younger Americans have, says Robert P. Jones, CEO of PRRI.

“They’re more likely, for example, to know someone or have a close friend or family member who is gay or lesbian, and that is a very strong driver of opinion,” Jones said. “Going forward, strong opposition to same-sex marriage, for example, as a driver of the culture war, is something that is destined to lose steam.”

In 1973, 70 percent of people felt same-sex relations are “always wrong,” and in 1987, 75 percent felt the same. By 2000, that number had dropped to 54 percent and by 2010 dipped to 43.5 percent.

This dramatic shift in public opinion is one of the fastest changes ever measured by the General Social Survey, which has been conducted every two years for the past four decades.

While basic demographic realities suggest greater openness is inevitable, changing how younger evangelical Christians interpret the bible is not.

Many younger evangelicals don’t know what to think theologically on this issue in terms of ‘Is same-sex marriage sinful?’,”  said Matthew Vines, author of God and the Gay Christian. “But they are willing to say, ‘In a pluralistic society, I don’t want to be infringing the rights of another group of people, whether I agree with them or not.’”

Matthew Vines at the annual meeting of the National LGBTQ Task Force in Denver, Colorado, Feb. 5, 2015.

Matthew Vines at the annual meeting of the National LGBTQ Task Force in Denver, Colorado, Feb. 5, 2015. (AP Photo)

Vines, a self-described gay evangelical Christian, left Harvard University after two years and established The Reformation Project, which uses biblical-based resources to make the religious case for same-sex marriage.

Vines points to six passages in scripture that refer to same-sex behavior in a negative light, which lead many Christians to believe all same-sex relations are prohibited.

“Paul, in the New Testament, is specifically describing same-sex behavior that is short term, that is fleeting, that is motivated by selfish, excessive desires, not loving, long-term faithful relationships,” Vines said.

A handful of evangelical churches in the United States softened their stance on same-sex marriage in the past year, but all lost members and donors as a result.

“There are significant institutional barriers to enduring change within evangelical churches,” Vines said. “This conversation is just getting started in the mainstream of the evangelical world and it will continue but I think it will take at least a decade to really affect a sweeping shift throughout American evangelicalism and even then there will be some more-conservative churches that are still holding out.”

Those still holding out appear to include influential Pastor Rick Warren and a group of Catholic and Evangelical scholars and intellectuals. They reportedly signed an eight-page declaration opposing the growing acceptance of same-sex marriages.

According to The Christian Post, the declaration is scheduled to be published in a religious journal this month and states, “An easy acceptance of divorce damages marriage; widespread cohabitation devalues marriage…But so-called same-sex marriage is a graver threat, because what is now given the name of marriage in law is a parody of marriage.”

Overall, the largest growth in support for gay marriage occurred among Republicans. Almost half, 45 percent, now support same-sex unions. However, Democrats (65 percent) and independents (54 percent) are still more likely than Republicans to support marriage rights for gay and lesbian couples.

When the survey first asked the same question in 1988, support for same-sex marriages was between 1 to 10 percent in all three groups.