ATHENS: Greece's parliament on Thursday overwhelmingly adopted a bill legalizing same-sex marriage and adoption in a landmark reform promoted by the conservative government despite opposition from the powerful Orthodox Church.

Once the law is promulgated, Greece will become the 37th country in the world and the first Orthodox Christian one to legalize adoption by same-sex families.

The bill, which was supported by the New Democracy party of Prime Minister Kyriakos Mitsotakis, was approved with 176 votes out of the 245 MPs present following two days of debates.

"This is a milestone for human rights, reflecting today's Greece — a progressive and democratic country, passionately committed to European values," Mitsotakis said on X, formerly Twitter.

A person hangs a LGBTQ pride flag on a light pole outside the Greek Parliament during a gathering with fellow supporters of the LGBTQ community as lawmakers vote on a same-sex marriage and adoption for same-sex couples bill on February 15, 2024 in Athens. Greece's Parliament was set to legalise same-sex marriage and adoption today, a landmark reform promoted by the conservative government over the opposition of the country's powerful Orthodox Church. (Photo by Aris MESSINIS / AFP)

When the result was announced, dozens of people waving rainbow flags celebrated in front of the parliament building in central Athens.

Although dozens of ruling New Democracy party legislators were expected to oppose the bill, support from opposition parties meant it was certain to pass.

Mitsotakis, who personally spearheaded the bill, had urged lawmakers to "boldly abolish a serious inequality" in Greek democracy that had rendered same-sex families "invisible."

The reform would "significantly improve the lives of quite a few of our fellow citizens, without taking away anything from the lives of the many," he added.

The vote had been hailed as historic by LGBTQ associations, who said same-sex families faced a labyrinth of administrative challenges amounting to discrimination under present family law.

When their children fall ill in Greece, non-biological parents currently have no right to decide what medical procedures are necessary for them.

Children do not automatically inherit from their non-biological parents.

If a child has two fathers, they can only be registered with the civil registry and covered by social services by entering the name of the biological mother.

And if the biological parent dies, the state can take away children from the other parent.

Dozens of Mitsotakis' conservative New Democracy party's 158 lawmakers were expected to oppose the bill or abstain.

However, support from the main opposition leftist Syriza party — its leader, Stefanos Kasselakis, is gay — the socialist Pasok party and other smaller parties meant defeat was almost impossible.

A simple majority in the 300-member parliament vote was needed for the bill to pass.

The Church of Greece — which has close ties to many government MPs — had said it was "totally opposed" to the reform, arguing that it "condemns" children to grow up in an "environment of confusion."

Archbishop Ieronymos, the head of the church, slammed the proposed law as part of a bid to impose a "new reality that seeks only to corrupt the homeland's social cohesion."

Some 4,000 people demonstrated in Athens against the measure on Sunday, many of them brandishing religious icons and crucifixes.

"It is said Greece is 30 years behind (the rest of the world). In such cases, thank God it is," the parliament spokesman for the hard-right party Niki said on Wednesday during the two-day debate.

Kasselakis, who married his partner in a US ceremony in October, has been subjected to homophobic insults, most recently from a central Greece mayor and an island group governor.

Mitsotakis was careful to stress last month that the changes would benefit just "a few children and couples."

The conservative leader, who comfortably won re-election in June, had promised to enact the reform during his second four-year term.

He announced it in January, just days after Kasselakis said Syriza would submit their own proposals for equality in marriage.

Greek LGBTQ families, who had maintained a low profile since the reform was unveiled last month, called for a celebratory gathering in Athens on Thursday.

"This is a day of joy," Rainbow Families Greece, an NGO helping LGBTQ families, said on Facebook.

Same-sex couples will still not be able to use assisted reproduction or a surrogate mother, procedures reserved for single women or heterosexual couples who have trouble conceiving.

Greece had been condemned for anti-gay discrimination by the European Court of Human Rights in 2013, after gay couples were excluded from a 2008 civil uni.

Opinion polls indicate that most Greeks support same-sex marriage but oppose surrogacy.

Under the Greek constitution, single parents, regardless of gender, have been allowed to adopt since 1946 — but until now the second partner in a same-sex union was left out of the process.

Under the previous Syriza government, Greece in 2015 legalized civil unions for same-sex couples, one of the last countries in the European Union to do so.

That law had resolved property and inheritance issues but made no provision for the adoption of children.