NEW YORK - Americans, regardless of generation, are deeply conflicted as they wrestle with the legality and morality of abortion, with large numbers identifying themselves as both "pro-choice" and "pro-life," according to a sweeping new survey.

While 56 percent say abortion should be legal in most or all cases, 52 percent say abortion is morally wrong.

The detailed and nuanced findings were released Thursday by the Public Religion Research Institute, based on a survey of 3,000 adults - one of the largest to focus on Americans' views of abortion.

The survey devoted particular attention to the views of young adults. It noted that 18-to-29-year-olds were far more likely than their elders to support same-sex marriage, but found there was no comparable generation gap regarding abortion.

The survey also tracked other polls over the last 12 years to highlight a sharp discrepancy in attitudes toward the two most prominent hot-button issues of the culture wars.

Views on abortion have been stable, with 56 percent of Americans telling Gallup pollsters this year that it should be legal in most or all cases, compared with 57 percent who said that in 1999.

Support for same-sex marriage has surged - from 35 percent in 1999 to 53 percent in 2011, according to Pew Research Center polls. A key factor relates to attitudes of the so-called millennials between the ages of 18 and 29.

"Millennials strongly support gender equality and rights for gay and lesbian people," the survey said. "However . . . younger Americans are no more supportive of abortion rights than the general population."

For example, 57 percent of millennials favor same-sex marriage, compared with 32 percent of baby boomers age 50 to 64. Yet, when asked about abortion, support for legal abortions was virtually the same - 60 percent among millennials, 59 percent among boomers.

Ambivalence was reflected in other responses from millennials: 68 percent said legal abortions should be available from health professionals in their community, while 46 percent said having an abortion was morally acceptable.

The Public Religion Research Institute, which conducted the survey with Ford Foundation funding, is a nonpartisan group that studies the intersection of religion and public life. CEO Robert Jones said both sides of the abortion debate were likely to see encouraging and discouraging findings.

"At the end of the day, Americans are committed to the availability of abortion, and conflicted about its morality," Jones said.

One notable finding pertains to the labels "pro-choice" and "pro-life," which are widely used by rival advocacy groups and are presented as either/or choices in most polls. In the new survey, 70 percent of respondents said "pro-choice" described them somewhat or very well, and nearly two-thirds similarly embraced "pro-life."

In all, 37 percent said they had a mixed identity - either embracing or rejecting both labels equally. Only 12 percent identified as "strongly pro-life" and 13 percent as "strongly pro-choice."

The survey was based on telephone interviews among a random sample of 3,000 adults in the United States, including 750 interviewed on cellphones. The margin of error is plus or minus 2 percentage points, higher for subgroups.