Dublin, Ireland: Polls opened in Ireland on Friday for a historic referendum on allowing same-sex marriage that is backed by all the main political parties but opposed by the Catholic Church.

Voters are being asked whether to add an article to the constitution saying: ‘Marriage may be contracted in accordance with law by two persons without distinction as to their sex.’

Polling stations will close at 2100 GMT and the result is expected on Saturday.

If the referendum is passed and once an ensuing law to support it is approved, Ireland would become the 19th country in the world and the 14th in Europe to legalise gay marriage.

Allowing gay couples to wed would be a seismic change in a country where homosexuality was only decriminalised in 1993 and where abortion remains illegal except when the mother's life is in danger.

The majority of Irish people identify themselves as Catholic, but the Church's influence has waned amid growing secularisation and after a wave of child sex abuse scandals that badly discredited the hierarchy.

The "Yes" side has been boosted by the support of sports, music and film stars including Irish Hollywood A-lister Colin Farrell and U2 frontman Bono.

Allowing gay couples to wed would be a seismic change in a country where homosexuality was only decriminalised in 1993, and where abortion remains illegal except where the mother's life is in danger.

‘The stories that I've heard over the last number of years from ordinary people, in ordinary jobs, this burden and pressure that's been on them, living in the shadows -- that can be removed on Friday by voting 'Yes',’ Prime Minister Enda Kenny said this week.

If the move is approved, Ireland would become the first country to make the change following a popular vote.

Referenda in Croatia and Slovenia both resulted in ‘No’ votes, although in Slovenia, parliament went ahead and approved gay marriage in March.

‘We are saying here, in a world first, that the people of Ireland can extend the right of civil marriage to all our citizens,’ Kenny said.

Currently there are 18 countries who have legalised gay marriage, most of them in Europe but also including South Africa, New Zealand, Canada, Brazil and Argentina.

Across the border in Northern Ireland, gay marriage is banned even though it is legal in the rest of Britain.

All of Ireland's main political parties, including conservatives, support amending the constitutional definition of marriage, and the latest polls put their camp in the lead.

But the result is by no means certain -- the Catholic Church has campaigned strongly for a ‘No’ vote, and many older and rural voters agree with the clergy.

‘My voting 'No' is not a vote against gay and lesbian people, it's against changing the definition of marriage,’ the archbishop of Dublin, Diarmuid Martin, told RTE state television on Wednesday.

‘I think you can have equality while recognising difference. For me, the fundamental thing is marriage and a family are about the complimentary gifts of a man and a woman, a mother and a father.’

The majority of Irish people identify themselves as Catholic, but the Church's influence has waned amid growing secularisation and after a wave of child sex abuse scandals that badly discredited the hierarchy.

Polls open at 7:00 am (0600 GMT) on Friday morning and close at 10:00 pm (2100 GMT), with the result not expected until Saturday afternoon.

Voters will be asked whether or not to add an article to the Irish constitution saying: ‘Marriage may be contracted in accordance with law by two persons without distinction as to their sex.’

The debate has become increasingly heated, with accusations from the ‘No’ campaign that their posters have been defaced and their supporters vilified.

The ‘Yes’ side has been boosted by the support of sports, music and film stars including Irish Hollywood A-lister Colin Farrell and U2 frontman Bono.

Irish expatriates living in Britain who are still eligible to vote have also started an online campaign, ‘Get the Boat 2 Vote’, to encourage people to travel home and support the change.

In another social media campaign, ‘Be My Yes’, Irish expatriates who can no longer vote posted messages and videos pleading on their countrymen to choose gay marriage.

Three opinion polls last weekend showed support for same-sex marriage ranging from 53 to 69 percent, while the ‘No’ vote is hovering between 24 and 26 percent.