The Portuguese constitutional court has today upheld the ban on same-sex marriage after a lesbian couple tried to use a constitutional loophole to challenge the law.

Teresa Pires and Helena Paixao, two divorced mothers in their 30s who have been together since 2003, challenged the country’s law when they were turned away from a registry office in Lisbon in 2006 after trying to wed.

The registry office rejected their attempt to marry on the grounds that the law states that marriage is between people of different genders.

The couple challenged the ruling on the grounds that the Portuguese constitution also forbids discrimination on the grounds of sexual orientation.

They took their case to a Lisbon court in 2006 but the case failed.

After considering their appeal, the constitutional court said in a statement that the constitution does not state that same-sex marriages must be permitted.

The five judges of the court are reported to have voted 3-2 on the appeal.

Paixao told Associated Press she regarded the decision as “a victory” because the split decision showed that attitudes were changing in Portugal.

“It shows there’s a change coming. Bit by bit people will come around and accept gay marriage,” she said.

The couple are planning on taking their appeal to the European Court of Human Rights.

Portugal, which has a large Roman Catholic population, has seen all previous efforts to instigate same-sex marriage hit by heavy resistance from the country’s religious groups and conservative politicians.

The country’s centre-left Socialist Party are, however, including a proposal to permit same-sex marriage in their manifesto for the upcoming general election, due to take place in September.