Muslims have voiced their protest, mainly in internet forums, and threatened the club over the third stanza of the "Blue and White, how I love you" anthem which fans have sung for decades and refers to Islam's main prophet Mohammed.
The passage Muslims consider insulting translates as: "Mohammed was a prophet who understood nothing about football, but from all the colours, it's the blue and white he would have picked."
Club authorities are taking the protest campaign very seriously.
"We've requested an expert on Islam to look into the question. While awaiting the result of his work we don't wish to say any more," a spokesman for the club said.
The Central Council of Muslims in Germany have refused to see the song as "blasphemous."
"The way it's phrased could anger some," conceded the Council's secretary general Aiman Mazyek, noting that the populations of both Gelsenkirchen and the Ruhr Valley comprised largely of the Turkish community.
"We're not demanding that the song be banned," he added.
More than four million Muslims live in Germany, most of Turkish background.