The genetic mother of twins born to a surrogate mother has won a landmark case at the High Court to be declared the legal mother of the twins.

Mr Justice Henry Abbott ruled that the genetic mother was the legal mother and was entitled to have a declaration from the court stating that.

He also said the twins were entitled to have the genetic mother named as their mother on their birth certificates.

The State had refused to allow the genetic mother to be listed as the mother on the twins’ birth certificates.

The surrogate mother was the sister of the genetic mother, and had not objected to the couple’s application.

Mr Justice Abbott said the input of the birth mother was to be respected and treated with “care and prudence”. But the old maxim mater semper certa est, motherhood is always certain, which the State argued meant the birth mother was always the legal mother, did not survive the enactment of the Constitution, “as it applies to the situation of in-vitro fertilisation”.

“To achieve fairness and constitutional and natural justice for both the paternal and maternal genetic parents, the feasible inquiry in relation to maternity ought to be made on a genetic basis and on being proven, the genetic mother should be registered as the mother,” the Judge said.

He also ruled that the word “mother” in Article 40.3.3 of the Constitution had a meaning “specific to the article itself”. This was related to the existence of the unborn only when the foetus was in the womb and not otherwise, he said.

The state had argued the Article, often referred to as the right-to-life amendment, had defined motherhood as the birth mother only.

Mr Justice Abbott also noted that in Ireland positive legislation on surrogacy was “totally absent” and so the contract entered into by the couple and the surrogate mother was “not illegal”. But he said its performance in the Irish legislative context “would not be enforceable by any court”.

Responding to the ruling, Solicitor Marion Campbell, on behalf of the family, said they were delighted with the outcome.

“It has been a very long, hard and emotional time for them and they would like to express their thanks for the support shown to them by their family, friends and legal representatives,” she said.

“It is to be hoped now that much needed legislation in relation to this whole difficult area of surrogacy will be brought in and that children born by way of surrogacy arrangements will have their rights enshrined in such legislation.