Recent polling clearly shows that Americans are much more accepting of same-sex marriage than they were a decade ago. All of the major national polls now find more supporters than opponents of same-sex marriage. But there is no consensus in the polling as to just how many Americans now actually think that same-sex marriage should be legal.

In the latest national surveys, all conducted this month, the percentages saying they favor legalizing same-sex marriage ranges from 49% in surveys by the Pew Research Center and Fox News, to 58% in a Washington Post/ABC News poll. Over the past 10 years, the Washington Post/ABC News question has consistently found more support for gay marriage than the Pew Research question. Between these ends of the spectrum, the CBS News and CNN/ORC polls find growing majorities favoring legalizing gay marriage.

It is not obvious what accounts for the differences in responses to these questions. They are all fairly worded and offer respondents an equal chance to express support or opposition to same-sex marriage. However, the differences may have to do with the extent to which legalization is emphasized in the question. The Post/ABC News survey gets the highest positive response to a question that simply poses whether it should be legal or illegal for gay and lesbian couples to get married. Questions that ask respondents if they favor or oppose legalization (Pew Research, Fox) evoke markedly less support. And a recent Quinnipiac poll, which asks respondents whether they support or oppose same-sex marriage – with no mention of legalization – gets a very thin margin of support; in that survey, 47% support and 43% oppose same-sex marriage.

In effect, it may be easier for a respondent to say legalize gay marriage than to say I favor legalizing it. That is at least one theory. However, perhaps the more important point is that while polling remains a fairly blunt instrument, it nonetheless can tell the story of an important social change that pundits and advocates might otherwise characterize in a self-serving way.

Andrew Kohut is the founding director of the Pew Research Center.

More from Pew Research on Gay Marriage.

Today, there is slightly more support for same-sex marriage than opposition to it, with 48% in favor and 43% opposed, according to our March 13-17 survey. In 2001, Americans opposed same-sex marriage by a 57% to 35% margin. A slideshow that tracks attitudes towards gay marriage since 2001, including breakdowns by religion, generation and political party, can be viewed here.

A significant majority of the public say same-sex couples should have the same legal rights as heterosexuals, but Republicans are divided on the question.

Two-thirds (66%) of the overall public say same-sex couples should have the same legal rights as heterosexual couples, according to the March survey. Opinions among Democrats and independents are almost identical – 74% in both groups agree. But Republicans are evenly divided – 49% say same-sex couples should have the same legal rights as heterosexual couples, while 48% disagree.

Much of the shift in support of same-sex marriage is attributable to the arrival of a large cohort of young adults – the Millennial generation – who are far more open to gay rights than previous generations.

The increase in support for same-sex marriage fueled by generational trends has been accompanied by the number of Americans who say they have changed their minds on the issue, according to our March poll.

In 2003, just 17% of those in the Silent generation – born between 1928 and 1945 – favored same-sex marriage; today 31% do. Overall, 28% of same-sex marriage proponents — representing 14% of all adults — say their views on same-sex marriage have changed.

The reason cited the most for changing views of same-sex marriage was having friends, family or acquaintances who are gay or lesbian.

Click on the image below to go to an interactive graphic that lets you sample responses from those who were surveyed.

Attitudes vary widely among religious groups.

The growth in support was substantial for white mainline Protestants. The March poll found 55% favor allowing gays and lesbians to marry legally, up from 36% 10 years ago. White mainline Protestants also changed their views on whether gay marriage went against their religious beliefs: 44% say gay marriage does conflict with their religiouss beliefs compared to 58% in 2003. White evangelicals (83%) say gay marriage conflicts with their beliefs, as do black Protestants (64%), and white Catholics (70%).

Surveys conducted during 2012 found wide regional differences on the issue.

Americans have become more accepting of same-sex couples as parents.

Roughly two-thirds (64%) agree with the statement that “same-sex couples can be as good parents as heterosexual couples,” up from 54% in 2003, according to the March survey.