U.S. groups traditionally opposed to same-sex marriage, including Republicans and white evangelical Christians, have become much less resolute in their opposition, a new Pew Research Center poll shows.

Sixty-two percent of U.S. respondents now approve of same-sex marriage, up from 57 percent when the U.S. Supreme Court legalized it in all 50 states two years ago and from 37 percent in 2007, according to the survey, released on June 26.

Overall, white evangelical Protestants continue to stand out for their opposition to same-sex-marriage with 35 percent of them favoring same-sex marriage, compared with a 59 percent majority who are opposed, the poll found.

"But younger white evangelicals have grown more supportive: 47 percent of white evangelical Millennials and Gen Xers – age cohorts born after 1964 – favor same-sex marriage, up from 29 percent in March 2016."

The poll found, however, that views among older white evangelicals (labeled Boomers and Silents) have shown virtually no change over the past year (26 percent now, 25 percent then).

The survey found growing support for same-sex marriage across affiliations with political parties, race and religion, with support strongest among younger Americans born after 1980 and Democrats.

Conducted June 8 through 18, the survey polled 2,504 people.    

Republicans were split on whether they approved or opposed same-sex marriage, with 48 percent against and 47 percent for, within the study's 3.5 percentage point margin of error for the group, Reuters reported.

That is a major shift from the 73 percent opposition a decade ago.

"The generational divide among white evangelicals is especially interesting, with nearly half of the younger folk approving of gay marriage," said Nancy Ammerman, a professor of the sociology of religion at Boston University, who was not involved in the poll, Reuters reported.

"When their parents were that age, there was barely a visible white evangelical gay person to be found."