According to a new study, news stories in the US are more likely to present pro-equal marriage viewpoints than those in opposition to it.

The Pew Research Center study, released on Monday, looked at 500 stories released between 18 March and 12 May 2013, and found that almost half primarily focussed on support for equal marriage.

While 47% of stories focussed mainly on support for equal marriage, 9% of stories were primarily focussed on opposition to it. 44% had a mixture of both pro and anti equal marriage viewpoints.

For the purpose of the study, a story is classified as primarily in support of or opposition to equal marriage, if views presented for one side outnumbered the opposing side 2-to-1. Other stories were classified as neutral or mixed.

The three major US cable news networks, CNN, Fox News and MSNBC, all featured stories which featured “significantly more”, pro-equal marriage statements than those against.

“This news media focus on support held true whether the stories were reported news articles or opinion pieces, and was also the case across nearly all media sectors studied,” wrote the study’s authors.

The study found that MSNBC had 30% mixed stories, 64% were primarily in support and 6% primarily opposed to equal  marriage. Fox News had 63% mixed, 29% supporting and 8% opposed, and CNN had 57% mixed, 39% in support and 4% in opposition to equal marriage.

The research also looked at postings on Twitter, and found that opinions both for and against equal marriage were closely aligned with public opinion on the issue.

The most common argument for same-sex marriage in news stories was that it is a civil rights issue. Arguments against equal marriage varies, and 18% of those included that it would hurt society.

“The findings show how same-sex marriage supporters have had a clear message and succeeded in getting that message across all sectors of mainstream media,” wrote the authors.