The parents of a child born through gestational surrogacy abroad have told the High Court there is an urgent need for his genetic mother to be legally recognised because his father is battling a life-threatening illness.

Kathy and Brian Egan from Kilkenny say the State's failure to allow for the legal recognition of the boy's genetic mother amounts to discrimination and a breach of his rights under the Constitution and the European Convention on Human Rights.

The arguments were made on the opening day of judicial review proceedings aimed at securing declarations from the court that the State has failed to uphold the rights of the child and has discriminated against him.

The State will defend the claims in a case which is expected to last a number of days.

In a sworn statement Kathy Egan described how surrogacy provided her and her husband with "a beacon of hope in an otherwise hopeless situation" to complete their family.

The court was told the couple had a son in 2009 but after repeated miscarriages and failed fertility treatments they opted to use a the service of a surrogate mother in Ukraine to carry their embryos and their second child was born in 2019.

Under current Irish law, Ms Egan cannot be registered or recognised as his legal mother.

Her husband Brian was granted a declaration of parentage and she was appointed his guardian when he reached the age of two. She said this status will lapse when he reaches the age of 18.

Shortly before the boy's second birthday, her husband received a "devastating diagnosis" in the form of an aggressive type of cancer.

She said the situation had "now become desperate" and they needed to safeguard their son's parentage as a matter of urgency as his only legal parent is battling a life-threatening illness.

Ms Egan said their son "is genetically 100% our child" and biologically and in every other sense a brother to their first son but they do not have the same rights as he is a legal stranger to her.

Senior counsel Mícheál P O'Higgins referred to a sworn statement by the couple's solicitor Annette Hickey who specialises in surrogacy.

In the statement, the couple's Ms Hickey said the practice of surrogacy gives rise to complex issues of child welfare and there is no international consensus on how to regulate it.

She said, however, that the European Court of Human Rights has held on a number of occasions that Article 8 of the European Convention on Human Rights requires states to provide for the possibility of recognition of parent-child relationships arising from surrogacy; at a minimum in all cases involving a genetic link between the child and the intended parents.

She said a 2018 study showed Ireland to have the second-highest rate of surrogacy among 90 countries.

Despite Irish intending parents having pursued surrogacy as a route to parenthood for upwards of three decades with numbers increasing in recent years, surrogacy has never been regulated in this jurisdiction, she said.

The general scheme of the Assisted Human Reproduction Bill 2017 had been published and part 6 of the Bill focused on the regulation of domestic surrogacy but does not address the issue of international surrogacy, the court was told.

In 2012 the Department of Justice issued guidelines in relation to international surrogacy as an interim measure pending the enactment of legislation.

The document provides guidance for genetic fathers but does not address the issue of the legal parentage of an intending mother who has a genetic link to the child.

The only option for a genetic mother to be legally recognised is through adoption but the Adoption Authority has said it may not consider such applications until legislation regulating surrogacy is enacted.

Mr O'Higgins said the failure to provide a mechanism for retrospective declaration of parentage for children born through surrogacy amounts to "invidious discrimination."

He said all the issues must be considered against the backdrop of the State never saying the surrogacy process was in any way unlawful or wrong.

He submitted that the State's failure to recognise or provide a mechanism for recognition of his biological mother contravenes the child's right to equality guaranteed by the Constitution by unfairly treating him differently to other children.

The case of the boy at the centre of this case could be contrasted with children born through donour-assisted human reproduction where parents with no genetic link to a child can apply for a declaration of parentage.

A failure to provide a similar mechanism amounts to discrimination, he said and while the state points to differences between to the two forms of assisted reproduction it was their submission that there is no distinctions sufficient to justify the treatment of the applicants in this case.

He added that "generalised concerns" that are undoubtedly bona fide about international surrogacy have limited relevance in the context of considering whether the discriminatory treatment is actually justified.

In their action against the State, the couple and their son seek declarations that the State has failed to vindicate their Constitutional rights due to their failure to provide a means by which Kathy Egan can be recognised in law as the mother of her youngest son.

They also seek a declaration that the State has failed to vindicate the child's rights under Article 8 of the European Convention of Human Rights and a declaration that the failure to provide for retrospective declarations of parentage for children born through surrogacy amounts to invidious discrimination contrary to obligations under the Constitution and the ECHR Act. They also seek damages.

The case continues tomorrow.