ATHENS, Greece (AP) — Lawmakers begin a debate Wednesday on a landmark bill to legalize same-sex marriage that would make Greece the first Orthodox Christian country to do so.

The Valentine’s Day session in parliament follows vocal opposition and protests from the church but also a shift in public opinion which — while still divided — is narrowly supportive of the reform.

If approved, the bill would grant same-sex couples full parental rights but not allow male partners to seek children born in Greece through surrogacy.

Here’s a look at the reform and why it’s happening now.

READ MORE For rights campaigner in Greece, same-sex marriage recognition follows decades of struggle Hundreds of protesters opposed to bill allowing same-sex marriage rally in Greek capital Students block Athens streets to protest private universities possibly coming to Greece

THE SLOW ROAD TO CHANGE

The journey toward legalizing same-sex civil marriage in Greece has been long and contentious, with governments in the past shying away from a confrontation with the Orthodox Church.

Civil partnerships for gay couples were made legal in 2015, with conservatives at the time opposing the initiative. Promises to extend those rights were repeatedly deferred as the country emerged from a severe financial crisis followed by the pandemic.

Many same-sex couples, meanwhile, chose to tie the knot in one of more than a dozen other European Union countries which already have marriage equality laws, bypassing restrictions they faced at home.

Early in his second term, center-right Prime Minister Kyriakos Mitsotakis is currently pushing through a series of difficult reforms, that also include tackling fan violence in sport and controversially ending an official state monopoly on higher education.

WHY IS THE CHURCH SO STRONGLY OPPOSED?

The Greek church’s opposition to the marriage bill has been emphatic.

The governing Holy Synod of senior bishops sent letters to all lawmakers outlining its objections. A circular with similar wording was read out during Sunday services at all Orthodox churches in the country, and religious groups have staged public protests against the proposal.

The church regards same-sex marriage as a threat to the traditional family model, arguing that support for that model could help address the declining birth rate in many European countries.

Support for that view in Greece has been expressed by other Orthodox countries, significantly including the Ecumenical Patriarchate which is based in Istanbul, Turkey.

Orthodox-majority countries, where churches take pride in continuity of tradition, are all located in eastern and southern Europe where public acceptance of gay rights has been broadly more apprehensive than in western Europe.

IS THE REFORM FINISHED?

Campaigners for LGBTQ+ rights are calling the bill a milestone reform, as same-sex couples would for the first time be recognized as a family unit.

Partners who are not the biological parents of the couple’s children would have to seek guardianship through adoption, which is more time-consuming than the process in many other European countries.

Transgender activists say they are likely to remain in legal limbo and are seeking additional changes to family law.

A RARE POLITICAL AGREEMENT

The political landscape surrounding same-sex marriage is complicated, but also offers a rare moment of consensus at a time when politicians across the European Union are keen to mark out their differences ahead of bloc-wide elections in June.

The Mitsotakis government is facing dissent from inside his own party and needs opposition votes for the bill to pass.

Many from the opposition are keen to back the reform. Stefanos Kasselakis, the opposition leader, last year became the first openly gay leader of a major Greek political party. Left-wing and centrist votes should provide a comfortable majority.

Political parties on the far-right are aligned with religious protests. They are unlikely to topple the bill but are seeking to draw support away from Mitsotakis’ traditional conservative base of voters.

The vote on the same-sex marriage bill is due Thursday.