The European Court of Justice has opened a hearing on the recognition of same-sex marriages in European Union countries where they are not legal.
The hearing in Luxembourg came after Romania's constitutional court asked the European court to make a ruling on the issue amid a court case in Romania brought by a Romanian-American couple who want their 2010 union to be recognised.
Same-sex marriage is not legally recognised in EU member Romania.
Iustina Ionescu, a Romanian lawyer, told the court the couple's marriage should be recognised based on the EU principle of free movement.
"We have confidence in the wisdom of the European judges that they will have the capacity to take a decision in our favour which corrects the injustices in Romania," said Adrian Coman, who has been fighting since 2012 to get his marriage to US citizen Claibourn Robert Hamilton legally recognised in the same way it would be if they were a heterosexual couple.
However, representatives from Romania, Hungary, Poland and Estonia told the court they do not want the term "spouse" to include same-sex unions.
European Commission officials said that same-sex marriages or civil partnerships are recognised or enjoy legal protection in 22 out of the EU's 28 members.
Romania, Poland, Slovakia, Bulgaria, Lithuania and Estonia currently do not offer legal protection to same-sex couples.
Opposition to same-sex relationships is often fierce in Romania, where homosexuality was only decriminalised in 2002.
Mr Coman and Mr Hamilton, who live in New York, travelled to Luxembourg for the hearing.