"Americans' acceptance of gays and lesbians as equal members of society has increased steadily in the past decade to the point that half or more now agree that being gay is morally acceptable, that gay relations ought to be legal, and that gay or lesbian couples should have the right to legally marry," the polling company said in a report detailing the results.

Gallup also looked to measure whether homosexual relations between consenting adults should be legal; nearly two in three Americans agree, while just over three in ten Americans believe there should be laws forbidding gay relations.

As expected, young adults, women and Democrats are the most supportive of gay rights. Interestingly, 58 percent of independent voters believe gay relationships are morally acceptable, and 57 percent of independents believe same-sex marriages should be legal.

Meanwhile, the South is the only geographic region where more than half of those surveyed did not support gay marriages or relations. And while non-Christian Americans are the demographic most likely to support gay relationships and marriage, only four in 10 Protestants support homosexual relations or marriage. Catholics are more accepting of gay relationships, with two-thirds describing them as "morally acceptable" and 51 percent saying they should be legal.

"Significant pockets of resistance remain — namely Republicans, those 55 and older, Protestants, residents of the South, and, in some respects, men — but majorities of other groups have grown comfortable with gay rights," Gallup said.

But there is some evidence that support for gay marriage may have plateaued temporarily, as attitudes on the subject have become cemented and demographics remain largely similar.

"While public support has been trending upward, support on all three measures was slightly higher in 2011 than in the new 2012 poll, suggesting attitudes may be leveling off — at least for the time being. However, they are stabilizing at a point that makes President Obama's decision to publicly support gay marriage much less controversial than it would have been even four years ago," Gallup said.