Minister for Justice Frances Fitzgerald has said a bill addressing assisted reproduction, including surrogacy, will be drawn up by the end of the year.

Ms Fitzgerald told RTÉ's Drivetime that she hopes legislation would be finalised in the lifetime of the current Government.

She said that the issue needs be addressed, but that it is complex, given clinical advances and developments in science in relation to fertility.

It comes as the solicitor for the woman who lost her legal battle to be declared the mother of her genetic twins, born to a surrogate, said her clients are hugely disappointed and felt they had a good case.

Also speaking on Drivetime, Marian Campbell said her clients are raising the twins and the surrogate is a sister of the genetic mother and had carried the babies as a "gesture of love".

She said Ms Fitzgerald needs to be aware that there are many families in similar circumstances and that the rights of children and mothers need to be addressed.

The Supreme Court today overturned a High Court decision declaring the genetic mother as the legal mother.

The landmark decision that maternity could be established on the basis of genetics and DNA and that the genetic parents could be named as the twins' parents on their birth certificates was appealed by the State.

Seven Supreme Court judges heard the appeal earlier this year.

Lawyers for the State had argued that the High Court decision was radically wrong and attempted to reverse the meaning of motherhood.

Lawyers for the family said the children had a right to have their links to their genetic parents recognised and protected.

The case came before the High Court last year, when the mother of the twins sought a declaration from the court that she was the legal mother of the children and could be named on their birth certificates.

She could not have children herself because of a medical condition, but her sister agreed to carry the embryos made by the woman and her husband at a fertility clinic.

The High Court gave a declaration that the genetic mother was the legal mother.

The Supreme Court overturned the High Court ruling in a six to one majority decision.

The genetic parents took the case after the Registrar of Births refused to register the genetic mother as the legal mother of the twins on their birth certificates.

The surrogate was registered as the twins' mother, while the genetic father was registered as their legal father.

In the appeal, the State argued a child's legal mother is the person who gives birth to them and that a child cannot, in law, have two mothers at the same time.

The State argued the definition of motherhood under public law was that the woman who carries the child to birth is the mother.

They said if someone else was to become the mother it cannot be by private contract but must be done by a process of public law, such as adoption.

The State said that if the High Court decision was allowed to stand, there would be consequences for many other women who had used donated eggs to have children.

Senior Counsel Michael McDowell had argued that the High Court decision opened up an appalling situation where these women would not be the mothers or guardians of their own children.

He said the decision gave rise to very serious difficulties for the interpretation of the Constitution and seriously compromised the capacity of the Oireachtas to deal with the issue of surrogacy and ascribing parentage.

Lawyers for the family argued that the children had a constitutional right to have the links to their genetic parents recognised and protected.

They said the ultimate proof of parentage was the presence or absence of genetic links established through DNA testing.

Their lawyers had rejected the suggestion that the High Court decision would lead to widespread legal difficulties for women who used donor eggs.

Senior Counsel Gerard Durcan said most donations are made anonymously or by agreement.

He said a birth mother would have rights unless or until someone else sought a declaration of parentage.

Surrogacy a matter for the Oireachtas - Denham

In her ruling, Chief Justice Susan Denham held there was no definition of mother in the Constitution.

She said there was nothing in the Constitution that would prevent the development of appropriate laws on surrogacy.

Ms Justice Denham said any law on surrogacy affected the status and rights of people, especially those of children, created complex relationships and had a deep social content.

She said it was quintessentially a matter for the Oireachtas.

Ms Justice Denham found there was a lacuna in the law and it should be addressed in legislation and not by the court.

Afterwards, the solicitor for the genetic parents, Marion Campbell, said the family was disappointed.

She said there were other families in similar situations. She said surrogacy was happening and legislation needed to be brought in.

Ms Campbell said children born as a result of surrogacy were exposed because there was no legal framework in Ireland to cover their rights.

Varadkar plans bill on surrogacy

Minister for Health Leo Varadkar this afternoon said: "Legislation on assisted human reproduction, surrogacy and gamete donation is long overdue. I intend to bring a memorandum for an Assisted Reproduction Bill to Government by year's end.

"I will consult with Justice Minister Frances Fitzgerald, my Government colleagues and others on the preparation of this bill. It is likely to deal with the issues of legal parentage, surrogacy, egg and sperm donation, and other related issues.

"Our prime concern here is that any law protects, promotes and ensures the health and safety of parents, others involved in the process such as donors and surrogate mothers, and most importantly, the children who will be born as a result of assisted reproduction."

Earlier today Ms Fitzgerald welcomed the Supreme Court's ruling.

She said: "I know that the ruling must be very difficult for the family involved. I am very sympathetic to the truly human circumstances at the heart of this case.

"The State had to appeal this case as it would have overturned our existing law and jurisprudence which sets the birth mother as a child's mother and because it would have fettered the Oireachtas in terms of what provisions it could make by law in those areas in the future.

"If Judge Abbott's ruling had been allowed to stand, hundreds of women who have given birth to children using donated eggs would have doubt cast on their status as their children's mother.

"Those women and their children now have legal certainty."

The minister continued: "I welcome that the Supreme Court has indicated that it is up to the Oireachtas to legislate for surrogacy.

"I note that the Supreme Court has said that it should be a priority for the Government to legislate for surrogacy and to provide for families such as that in this case.

"My colleague, Minister for Health Leo Varadkar TD, will be bringing proposals to Government before the end of the year."

A senior lecturer in law at UCC has said legislation should be urgently introduced to deal with surrogacy.

Speaking on RTÉ News at One, Deirdre Madden said that other jurisdictions had decided similarly that the woman who gives birth to a child is the legal mother but they then introduced statutory frameworks to enable legal relationships to be formed between the children and the genetic parents.