"Embryo Freezing in Disarray", stated the front-page headline in this week's Irish Catholic. While a third Irish fertility clinic is about to start freezing embryos, the clinic at University College Hospital in Galway says it will not be following their lead. Instead, it is taking a more "Catholic" approach, which it believes is more in keeping with the recently published Medical Council guidelines on ethics.

As the headline implied, the matter is open to interpretation and confusion. Delivering the inaugural lecture to UCD's Physiology Society this week, Dr Tony Walsh, consultant gynaecologist, called for the establishment of a regulatory authority to oversee reproductive medicine in Ireland. Dr Walsh, a gynaecologist at the State's newest fertility unit, The J. Marion Sims Clinic, said it should be similar to the UK's Human Fertilisation Embryology Authority.

Dr Walsh said: "We need this in Ireland to supervise clinics providing these technologies. The revised medical guidelines from the Medical Council are welcome but a specific overseeing body is required. As one of two IVF clinics in Dublin we would greet such a development with open arms." He added that he welcomed indications that Health Minister Brian Cowen intended to set up such a body.

It was more than simply a medical matter, he said, and would require input from sociologists, theologians and others.

Dr Declan Egan of the fertility clinic in University College Hospital Galway said their plans were to freeze "pro-nuclear eggs". He said that this was where the sperm head was inside the egg but the two nucleii had not come together. It was when the latter happened, said Dr Egan, that most people considered the point of fertilisation. "Up to that point it is reversible. The Medical Council say we can freeze eggs but make no comment on embryo-freezing. We are very cautious about that."

He said the Medical Council stipulation that all embryos generated must be used for normal implantation was simply not practically possible, and even if frozen they would have to be destroyed if not used within five years. Their approach, he believed, was more acceptable to Catholics. "I have certainly met Catholic ethicists who find it acceptable."

The Medical Council guidelines do not explicitly forbid embryo-freezing. The new ethics guide for doctors states: "Any fertilised ovum must be used for normal implantation and must not be deliberately destroyed."

At the fertility clinic in the Rotunda Hospital in Dublin, couples attending sign a form allowing for the destruction of unused fertilised eggs after they have been frozen for five years.

Embryo cryopreservation, or freezing, as it is commonly known, is a method of sustaining the viability of embryos by cooling them and storing them at a very low temperature. Embryos can be transferred to the uterus or the fallopian tubes at the appropriate time in a future cycle. Depending on the fertilisation method used, two or three embryos are selected for transfer, and any embryos in excess of this can be cryopreserved. The benefit to the woman is the possibility of subsequent embryo replacement without having to undergo further treatment.

At the new £1 million J. Marion Sims Clinic, Rathgar, Dublin, embryo-freezing began last week. According to the clinic's senior embryologist, Ms Athina Tsouros, who works with Dr Walsh and gynaecologist Dr David Walsh, the clinic carries out "everything the Medical Council will permit us to do in tubal surgery".

"We welcome the recent changes while recognising that it is a very complex issue. Whilst we are not perfunctory in our actions, our unit is designed to help people have a child in the context of family values. As far as we are concerned, embryo-freezing is permitted under the guidelines and we are offering it," she said.

The clinic has already considered the situation in five years time when the unused frozen embryos may face destruction as a result of couples separating, emigrating or dying. "We are looking at whether we could offer the embryos for adoption. Our consent form says that responsibility for the embryos lies with the couple and the clinic. In the event of them not being used adoption seems like a very good option.

"A couple who could not achieve fertilisation and could not get embryos should be offered these embryos. It is done routinely in clinics in the UK. However, we are waiting for evaluation of this and we will not destroy embryos. They will be kept here until guidelines are drawn up," she said.

Ms Tsouros said 2,600 couples sought IVF treatment in the State annually, with a success rate of up to 30 per cent. While there were 65 units in the UK, there were only four units, including the J. Marion Sims Clinic, operating in Ireland.

"We are open since after Christmas and the level of interest has been very high. We are considering setting up satellite clinics outside of Dublin."