An MP has suggested heterosexual couples are being discriminated against because they are unable to sing the hymn Jerusalem at their weddings.
Labour's Chris Bryant said it was banned by many churches because it was "not addressed to God", yet banned from civil ceremonies for being religious.
But he told MPs that, under government plans, gay couples who have a civil partnership would be able to sing it.
The Home Office said the rules were the same for all couples.
The words of Jerusalem are a poem by William Blake, which starts: "And did those feet in ancient time, Walk upon England's mountains green?"
It has become a favourite choice for crowds cheering on England at rugby and cricket matches, and was also included in Prince William and Kate Middleton's wedding ceremony.
But in the past, a number of major churches, including Southwark Cathedral in London, have banned it on the grounds that it is too nationalistic.
'Reserved for homosexuals'
Mr Bryant, who is himself gay, called for a Commons debate on the matter, telling MPs: "If you're a heterosexual couple and you get married in church many clergy will refuse to allow it to be sung because it's not a hymn addressed to God.
"If you get married as a straight couple in a civil wedding you're point blank not allowed it because it's a religious song.
"If, however, you're a gay couple and you have a civil partnership, under the government plans you will be allowed to sing Jerusalem.
"So can we just make sure that Jerusalem is not just reserved for homosexuals."
His comments were met with laughter in the House.
In response, Commons leader Sir George Young said: "I think Jerusalem should be played on every possible occasion."
Mr Bryant, who is MP for Rhondda and a former Foreign Office minister, made history in 2010 when he and his partner took part in the first civil partnership ceremony to be held in the Palace of Westminster.
At present, civil unions of any kind - gay or straight - cannot take place on religious premises, although any couple can have a religious service later at a place of worship to celebrate.
Under a government proposal, currently open to consultation, same-sex couples would be able to have their civil partnership and and religious service on the same - religious - premises.
A Home Office spokeswoman said there were no plans to change the law to allow heterosexual couples to do the same because they already had the choice about whether to get married in a religious venue or not.
"Our proposals make clear the civil partnership registration would remain secular and distinct from any religious service," she said.
"The rules of what is contained in a secular or religious ceremony are no different for same-sex or-opposite sex couples."