A Swiss embryologist has told the High Court that where an embryo has been generated, there must be a wish to generate children.
Prof Gunter Rager was responding to remarks by John Rogers SC, for a man who is opposed to having three frozen embryos returned to his estranged wife, that the 44-year-old man did not wish to have any more children with his wife.
The embryologist said: "You cannot change your attitude."
He said it was "not understandable" that the woman, who has said she regards the embryos as "her children", would not be given the right to use the embryos to have children.
It was his view - and the view of most embryologists, including Irish embryologist Dr Ronan O'Rahilly - that an embryo is a "dynamic self-organising system" and "new human being" who is engaged in dialogue with the mother from the point of fertilisation, Prof Rager said.
That point marks the beginning of individual human life and it was "arbitrary" to suggest that human life began at later stages, such as implantation of the embryo in the uterus, the development of eight cells, development of the nervous system or the feeling of pain.
It was also a "naturalistic fallacy" to argue that because many embryos did not survive after fertilisation, then they could not be regarded as individual human life, he said. That was akin to saying that because many people perished in the tsunami disaster, human life had no value.
He agreed the science of embryology had developed only from the late 19th century but rejected a suggestion by Mr Rogers that the greatest concern of embryologists is the protection of children "in the womb".
"We have to protect individual human beings," he said. A zygote or embryo was an individual human being and a complete genome from fertilisation on. It was wrong to describe it as just a collection of cells.
When Mr Rogers suggested a human was essentially defined by culture and that the question of what was human depended on the period in which that issue is considered and should be determined by reference not just to biological but also cultural questions, Prof Rager said culture was created by humans with a human genome.
This was not an ethical test but a purely biological test and the debate must be held on the basis of science as it was today, he said.
"We can't go back to the 15th century - we live today."
If science said that a zygote was an individual, one could not say from the point of view of ethics or culture that it was not an individual, he said.
Prof Rager, who also holds doctorates in medicine and philosophy and is director of the Institute of Anatomy and Embryology at the University of Freiburg, Switzerland, was giving evidence in the continuing action by a 41- year-old mother of two against her estranged husband and the Sims fertility clinic, Rathgar, Dublin, with the Attorney General as a notice party.
The woman is seeking to have returned to her three embryos which were frozen in the Dublin clinic following IVF treatment undertaken by the couple in 2002 which led to the birth of their second child.
Mr Justice Brian McGovern has ruled the husband did not consent to the embryos being implanted in his wife's womb and he is now hearing evidence to determine issues of public law, including when human life begins.
Yesterday, Prof Rager told Inge Clissman SC, for the woman, that there was a continuous development of the embryo from fertilisation on and arguments that human life began at various other stages after fertilisation were arbitrary and "very doubtful".
His view of when life began was from a scientific, not a religious or ethical viewpoint, he added. Various scientific textbooks supported what he said. Implantation did not alter the nature of the embryo; an embryo could be placed into an artificial uterus and develop there.
"It has all the potential in itself" and some five scientific capabilities.
The case continues today.
