WASHINGTON -- Republican voters, like the American public as a whole, are growing more and more supportive of equal rights for lesbian, gay, bisexual and transgender individuals. Recent polling shows that about a third of Republicans back marriage equality, with the percentage much higher among young conservatives. In the general population, a firm majority now supports the freedom to marry.

"Everybody's moving on this," said Alex Lundry, chief data scientist at the GOP polling firm TargetPoint, during a Human Rights Campaign event Thursday. "In fact, you cannot name any demographic that has not shown a growth in support for this over the last 10 years, whether it's Republicans, Republican primary voters, conservatives, evangelicals. Everybody's growing. So while 30 percent, 33 percent may seem very low, the movement that we've seen there is just remarkable. And it's going to keep growing."

But that wave of change has not yet hit the GOP candidates running for Congress this cycle. A small handful of Republicans do back marriage equality, but many of them are still stuck in primaries and are considered long shots to get their party's nomination.

There is movement elsewhere, however. The Republican Party could have its first openly gay member elected to Congress if Carl DeMaio in California, Dan Innis in New Hampshire or Richard Tisei in Massachusetts wins his election.

And many supporters of marriage equality argue that being anti-gay is no longer a prerequisite to being seen as a strong conservative.

"Most Republican candidates may not be embracing gay marriage, but, unlike in past elections, they are not running against it. And that is progress," said Republican strategist Mark McKinnon.

Of that group, only Wehby is considered a frontrunner for her party's nomination. But if she wins, she'd be facing Sen. Jeff Merkley (D-Ore.), who is one of the Senate's most outspoken supporters of LGBT equality. Merkley also introduced the Employment Non-Discrimination Act, which would bar workplace discrimination on the basis of sexual orientation or gender identity.

On the House side, DeMaio is considered a top GOP prospect. Last month, in what may be the first such spot by a candidate from either party, he aired an ad featuring his partner. But he has faced resistance from some in the LGBT community for not being supportive enough of advancing equality.

Tisei, who married his partner last summer, recently announced he would be boycotting the state GOP convention because of its socially conservative, anti-gay platform.

In Innis' primary fight, he is facing Frank Guinta, who opposes marriage equality. The former dean of the University of New Hampshire business school, Innis married his partner in 2009, when same-sex marriage became legal in the state.

In an interview with The Huffington Post, Innis said LGBT issues have largely been a non-issue among Republican voters in his race.

"Voters don't seem to care, at least here in New Hampshire," he said. "I think that 'live free or die' mentality ... carries through on issues of this sort. The issues that people are focused on are those around fiscal responsibility and jobs and the economy."

Gregory T. Angelo, president of Log Cabin Republicans, said having an openly gay member of the Republican caucus would be an important step in helping the party evolve even further.

"Having a gay Republican in Congress who can make the case that you can be a gay individual who is a strong Republican and also a strong conservative in the House of Representatives would shift the GOP messaging on this," Angelo said. "It might change which bills are introduced, and perhaps more importantly, which bills are not introduced, in the 114th Congress."

"And in a similar way that gay individuals living their lives openly and honestly to their friends, neighbors and family members has shifted public opinion around the country on these issues," Angelo added, "I think having a gay Republican or gay Republicans who are living their lives openly and honestly in the House of Representatives could generate a similar shift in opinion among the Republican caucus in the United States House of Representatives."

In Connecticut's 4th Congressional District, both ophthalmologist Joe Bentivegna and former state Sen. Dan Debicella, who is considered the frontrunner for the GOP nomination, back marriage equality.

Bentivegna told The Huffington Post he has been asked several times about his stance on same-sex marriage.

"I would say that most Republicans have accepted marriage equality in Connecticut," he said. "One member of the tea party disagreed with me on the issue. I got a little 'flack' for it, but not much."

Bentivegna, Debicella, DeMaio, Tisei or Innis would each be taking the place of a House Democrat who already supports LGBT equality. At this point, the issue of marriage equality is essentially universally accepted among Democrats, with support for same-sex marriage written into the Democratic Party platform.

The Republican Party's platform, in contrast, still defines marriage as being between one man and one woman -- a stance that is creating an internal rift, especially between the older and younger generations of the party.

According to a new poll by Greenberg Quinlan Rosner Research and TargetPoint, done for the Human Rights Campaign, 42 percent of likely Republican voters between the ages of 18-29 back marriage equality, compared to just 25 percent among voters 50 and older. Another recent poll by Pew Research found an even starker divide: 61 percent of Republicans and those who lean Republican in the 18-29 age group back same-sex marriage rights, compared to just 27 percent of Republicans ages 50 and older.

And in the last two years, support for marriage equality has also been growing in pockets of the country more traditionally opposed to it, with more people in the deep South and rural areas backing same-sex marriage.

"This is the most rapid and stunning shift in American public opinion that we've seen in the modern political era," Lundry said last week of the growing support for marriage equality generally. "This is moving faster than any issue we've ever tracked or ever seen. It is truly amazing what we've seen in the last 10 years."

Marc Solomon, national campaign director at Freedom to Marry, also said the shift is "historically remarkable."

"There's a real convergence of several factors," he said. "More people getting to know gay and lesbian couples, more people understanding why gay couples want to marry, the generational effect and more leaders coming out in support. I think all of that works together to create a drumbeat and people are really rethinking their positions and shifting them."

Conservative stalwarts like former Vice President Dick Cheney, former Republican National Committee Chair Ken Mehlman, Sen. Rob Portman (R-Ohio) and former Sen. Alan Simpson (R-Wyo.) have all come out in favor of marriage equality. Last year, more than 100 Republicans signed a brief to the Supreme Court in favor of LGBT equality as well.

LGBT advocates were heartened by a recent election in Illinois as an example of how Republican voters may be ready for candidates who embrace the freedom to marry.

On May 18, three Republicans in the Illinois state House were heavily targeted by same-sex marriage opponents after they backed a marriage equality bill. Yet all three beat their primary opponents in the election.

"Honestly, that's been the toughest place for us, is low-turnout Republican primaries," Solomon said. "And I think what happened yesterday shows we really turned the corner."

It's not especially surprising that elected officials and candidates are slow to catch up with the grassroots. After all, it wasn't until May 2012 that President Barack Obama announced his support for marriage equality -- long after many people in his party had already adopted that position.

"This is the case for many causes and many issues, which is that the people will lead and the politicians will follow," said Solomon.

It seems likely that in 2016, there will be even more Republican candidates who back marriage equality. But getting a presidential nominee who has that position may be tougher, with many of the field's frontrunners currently against it.

And the religious right isn't planning to go away. The latest tactic has been on the "religious freedom" front, which would allow businesses to deny service to gays and lesbians.

"The fight has to be over what the First Amendment is," John C. Eastman, chairman of the anti-gay National Organization for Marriage, recently told the Washington Post. "This is not somebody adhering to old Jim Crow lunch-counter discrimination. This is a fundamental dispute about what marriage means, and why it’s important for society."

Other GOP candidates are still speaking out on the issue as well. Ed Gillespie, the former chair of the Republican National Committee who is trying to unseat Sen. Mark Warner (D-Va.), recently criticized a federal judge's decision overturning the state's ban on same-sex marriage. Lee Bright, a former state senator who's challenging Sen. Lindsey Graham (R-S.C.), has also called for the impeachment of a federal judge who struck down Utah's marriage equality ban.

But when asked whether he was confident that the GOP will have shifted enough to have a pro-marriage equality presidential nominee in 2016, Angelo of the Log Cabin Republicans replied, "That's kind of the big question that everyone's asking me. I think that my time in Washington has certainly taught me that anything is possible."