Identical Belgian twins who were not terminally ill have been killed by lethal injection in a case believed to be the first of its kind.
Marc and Eddy Verbessem, who were born deaf, sought euthanasia after discovering they were both going blind.
They believed their lives would not be worth living if they could not see each other, according to their brother.
It has emerged that the pair, aged 45, had to overcome strong resistance from their family to be killed.
Their local hospital refused to euthanise them, and raised doubts about whether their situation met the requirements of Belgian legislation.
A professor of medical ethics at Leuven in Belgium criticised the killing saying: “In a society as wealthy as ours, we must find another, caring way to deal with human frailty.”
Under Belgian law a doctor must judge that a patient is unbearably suffering, and the patient must make clear their wish to be killed.
However in this case neither were suffering extreme physical pain nor were terminally ill, according to media reports.
Their local hospital said the law is “clearly open to various interpretations”, but warned that if any blind or deaf person is allowed to be killed then the country would be moving far away from what the legislation intended.
Professor Wim Distelmans, the doctor who allowed the killing, said: “It is certain that the twins meet all the conditions for euthanasia”.
Chris Gastmans, professor of medical ethics at the Roman Catholic University of Leuven asked: “Is this the only humane response that we can offer in such situations?
“I feel uncomfortable here as ethicist. Today it seems that euthanasia is the only right way to end life. And I think that’s not a good thing.
“In a society as wealthy as ours, we must find another, caring way to deal with human frailty.”
Belgium was the second country in the world after the Netherlands to legalise euthanasia.
Last month it was revealed that Belgium is considering allowing children and Alzheimer’s sufferers to ask to be euthanised.
Dr Peter Saunders, director of UK-based campaign group Care not Killing, has warned: “Once you relax the law on euthanasia or assisted suicide steady extension will follow as night follows day.”