( CNN ) -- Fewer than half of Americans oppose legalized same-sex marriage , according to a new poll on the issue released Wednesday , with significant shifts in public opinion on the issue just since last year . More Americans continue to oppose gay marriage than support it , according to the poll , which was released Wednesday by the Pew Research Center . But for the first time since Pew starting asking about same sex marriage 15 years ago , fewer than half of those polled said they oppose legalizing the institution . The poll revealed other firsts . For the first time since Pew began asking about the issue , more white mainline Protestants and white Catholics favor gay marriage than oppose it . `` The shift in opinion on same-sex marriage has been broad-based , occurring across many demographic , political and religious groups , '' Pew 's polling analysis said . The analysis noted that political independents , who were opposed to gay marriage by a wide margin just last year , are now divided on the issue . The poll -- which combines two surveys conducted from July to September of this year -- found that 42 percent of Americans favor same-sex marriage , while 48 percent oppose it . In polls conducted in 2009 , 37 percent favored gay marriage while 54 percent were opposed , Pew said . `` The public continues to be far more supportive of gays and lesbians serving openly in the military than of allowing legal same-sex marriages , '' the Pew 's polling analysis notes . Sixty percent of Americans favor allowing gays and lesbians to serve openly in the military , while 30 percent oppose it . Support for gays serving openly in the military has remained fairly stable over the last five years , Pew said . On gay marriage , the new poll found significant differences of opinions along age , racial and partisan lines . Americans in the so-called Millennial Generation -- those born after the 1980s -- favor gay marriage by 53 percent to 39 percent , the poll found . Among those born between 1928 and 1945 , just 29 percent favor allowing gays and lesbians to marry legally , while 59 percent are opposed . Among Democrats , 53 percent support legalized gay marriage , while just 24 percent of Republicans do . And while whites are evenly divided over gay marriage , the poll found , blacks oppose legalizing the institution by a wide margin .
For the first time in Pew poll 's history , fewer than half oppose legal gay marriage . More Americans continue to oppose gay marriage than support it . Poll finds significant shifts in public opinion on the issue since last year .