Same-sex spouses may soon be legally recognised in all EU countries.

The European Court of Justice has pushed for same-sex spouses to receive residential rights, even in countries not offering equal marriage rights, after stating that the definition of marriage has “evolved”.

Melchior Wathelet, advocate general for the ECJ, said the idea that “the term ‘marriage means a union between two persons of the opposite sex’ can no longer be followed”.

“While member states are free to provide for marriage between persons of the same sex in their domestic legal system or not, they must fulfil their obligations under the freedom of movement of EU citizens,” they added.

Related: Gay couple tie the knot just minutes after Australia legalises same-sex marriage

Adrian Coman lives in Romania, one of the six EU countries that have no legislation relating to same-sex marriage or civil partnerships.

His spouse Clai Hamilton, an American, was denied a residence permit from Romanian authorities as marriage equality hasn’t been introduced in the country, nor is it recognised in law.

The couple, who married in Brussels, appealed against the decision on the grounds of discrimination – which has since been seen by the ECJ.

Under EU law, the spouse of an EU citizen has the freedom to join his or her spouse in the member state where the latter resides.

Mr Wathelet brought up the ambiguity of the word ‘spouse’ which doesn’t specify exclusion of same-sex couples.

A final ruling on the case is pending.

Words Liam Gilliver