The State is appealing a High Court ruling handed down in April in the joined cases of X and Y, in which Ms Justice Siobhán Phelan identified a “legislative lacuna” requiring Oireachtas intervention.

The cases relate to two families whose children were refused Irish passports in circumstances where they were born abroad to same-sex couples relying on donor-assisted human reproduction (DAHR) procedures.

In the case of one of the families, anonymised as X, the parent who is an Irish citizen was neither the gestational mother nor the biological father of the child. In the other family, Y, the biological or genetic mother of the child is an Irish citizen.

A central issue in the High Court proceedings was the interpretation of “parent” under section 7(1) of the Irish Nationality and Citizenship Act 1956.

The Supreme Court appeal was heard over three days last week, with Conor Power SC and William McLoughlin BL appearing for both families, instructed by Gibson & Associates LLP.

The Irish Human Rights and Equality Commission intervened as amicus curiae, making written and oral submissions on human rights and equality issues.

The Commission argues that in failing to provide for a legislative pathway to pass citizenship by descent to the children in these cases, the State has breached the equality provision under Article 40.1 of the Constitution.

The Supreme Court reserved its judgment at the conclusion of the three-day hearing. It is expected to be published sometime next year.

Liam Herrick, chief commissioner of the Irish Human Rights and Equality Commission, said: “We were grateful for the opportunity to assist the court in these joined matters, which raise profound questions about how citizenship by descent is passed to children born abroad through shared motherhood IVF.

“We look forward to the court’s judgment in due course.”