In the Republic of Ireland, same-sex couples can enter a civil partnership, but now the debate has moved on to whether or not they should be permitted to marry.
New laws to allow gay marriage are expected to be introduced in England and Wales before the next election in 2015.
There are no plans for similar legislation in Northern Ireland, assembly members as recently as October rejected a proposal that same-sex couples should have the right to marry.
But the issue of gay marriage is on the political radar in the Republic.
In Dublin, a group of tourists are taking photographs of Leinster House - home of the Irish houses of parliament - through the railings on Kildare Street.
Jackie Mullins is standing close by, holding a large placard.
"I'm in support of the right of gay and lesbian persons to marry in this country" she said
If we want to see an Ireland of equals then the next logical step for me is the achievement of marriage equality”
Jerry Buttimer, Fine Gael
"I don't believe that the state should pick out people on the basis of their sexual orientation and gender and say to them, 'you're the wrong orientation so we're going to say you can't get married'.
-more at BBC News