ATHENS, Greece (AP) — The center-right Greek government’s plans to legalize same-sex civil marriage received a major boost Thursday after the left-wing opposition leader pledged his party’s backing in parliament.

Syriza leader Stefanos Kasselakis said he would instruct his lawmakers to vote for the proposal, although he argued that it didn’t go far enough on parenthood rights.

Kasselakis, who married his male partner in New York in October, has expressed the desire to acquire children through a surrogate mother.

Syriza’s support would practically ensure the draft law’s approval in the 300-seat parliament.

Other news Greek government says it stands by same-sex marriage pledge even after opposition from the Church Greece approves new law granting undocumented migrants residence rights, provided they have a job As ties warm, Turkey’s president says Greece may be able to benefit from a Turkish power plant

The governing New Democracy party has 158 lawmakers, but about a dozen have voiced objections to the proposal — which has also met with reservation from the country’s influential Orthodox Church. However, the backing of Syriza’s 38 lawmakers should suffice to tip the balance.

Kasselakis said in an interview with private Star TV that despite its “imperfections,” the proposal Prime Minister Kyriakos Mitsotakis unveiled Wednesday contained “some positive elements,”

Kasselakis also criticized the prime minister’s refusal to force all New Democracy lawmakers to back a human-rights issue as “political cowardice.”

Nevertheless, he said, “when this draft law comes to parliament, it will be approved thanks to Syriza.”

According to Mitsotakis, the reform would allow civil marriage for same-sex couples but preclude them from acquiring children through surrogate motherhood in the future. Full parental rights would be granted to same-sex couples that already have children.

A draft law on the same issue that Syriza tabled earlier this week would have accorded same-sex couples the right to parenthood through surrogate mothers.

The country currently only allows that procedure in the cases of women — single or married — who are unable to bear children on health grounds. As well as heterosexual couples, single men or women are allowed to adopt. Greece legalized same-sex civil partnerships in 2015.

Opinion polls suggest Greeks are evenly divided on the issue of same-sex marriage, but opposed to extending full parental rights to gay or lesbian couples. The raising of children by same-sex couples was also the main focus of the Church’s objections.

The full details of the government’s proposal are expected to be released within the coming days. Once that happens, it would take several weeks for it to come to parliament for approval.

Four smaller center-left and left-wing parties in parliament have not specified their stance on the proposal, while three small right-wing parties strongly oppose it.