A leading medical specialist has told the High Court it is "tragic" that couples have to go to court to resolve issues on reproductive medicine because of an absence of legislation.

Dr Mary Wingfield was giving evidence in a landmark case involving the mother of twins born to a surrogate who wants her name recorded on the register of births.

Dr Wingfield, who was a defence witness for the State, said she was "very, very disappointed" that seven years after a report from the Commission on Assisted Reproduction, there is still "no clarity and no legislation".

She said: "We so badly need legislation, it is tragic that couples have to end up in the High Court to resolve issues like this. It is not right."

Dr Wingfield agreed that a majority of the commission had recommended seven years ago that "commissioning parents" of a child born to a surrogate mother should be "presumed" to be the parents as that was the original intention.

But she said it was a very complex area because of the different scenarios involved and the genetic make-up of the children and whether or not they were genetically linked, through egg donation, to the gestational mother.

It was important to protect the rights of a surrogate mother as well, she added.

Dr Wingfield felt parentage should lie with the "commissioning couple" as it was always intended a child born to a surrogate would be theirs but it is difficult to legislate for it.

The principal of intent was the primary one in her opinion rather than just genetics, as you had to allow for opposite situations where a woman received a donor egg to have children and she would want to have parental rights over the child.

Dr Wingfield said because of the lack of clarity and legislation Irish couples requiring surrogacy had to generally go abroad.

She agreed the Commission on Assisted Reproduction had used the word "presumption" of parentage for genetic mothers because that gave more flexibility than an absolute.

Earlier, the court was told there are no written guidelines or policies to deal with cases of registering surrogate births in Ireland.

Chief Registrar Kieran Feely said the State's policy was not written in any formal document, but was passed on to him verbally by his predecessor.

The case is the first of its kind in Ireland and will see issues of genetic parentage being considered for the first time by an Irish court.

During cross-examination by Gerard Durkan SC, Mr Feely said he had received legal advice that only the woman who gave birth to a child could be registered as the mother.

While he had been aware of this policy from his predecessor, nothing was reduced to writing.

He also said he had received DNA evidence in the current case to show that the applicant was the biological mother of the twins and the surrogate mother was not the biological mother.

The court also heard that in other jurisdictions, such as the UK, legislation is in place to deal with surrogate births and provision is made to register a transfer of parental duties to a genetic parent.

A similar system exists in Ireland, but only in cases of adoption, he said.