He’d be better off dead.

How often do we hear that judgment on the apparently miserable life of an elderly relative who has survived a stroke or heart attack or radical surgery? When they lose the capacity to communicate and a decision has to be made about whether to resuscitate them or offer life-prolonging treatment, at least family members can try to make a decision based on what that person would have wanted. Even that is fiendishly difficult because, faced with a stark choice, a patient’s definition of “a life worth living” can change dramatically.

In a world threatened by a population explosion, it is ironic that huge resources are being invested in preserving and extending life. Quantity seems to have eclipsed quality. In modern western culture, death is equated with failure and doctors are increasingly reluctant to “let nature take its course”, for fear of being sued.

Simultaneously, at the beginning of life, technology is ensuring the survival of thousands of babies who would have died 20 years ago, though many will be left with profound, lifelong disabilities. Currently, Britain has more than 100,000 under-18s on Disability Living Allowance.

When the person on the ventilator is a small baby unable even to communicate the feeling of pain, these life or death decisions are even more heartbreaking. A desperately sad human drama was brought to a premature end in Court 50 in the Royal Courts of Justice in London this week when the parents of a 13-month-old boy, known only as Baby RB, asked Lord Justice McFarlane to decide the fate of their child.

King Solomon’s dilemma was a push-over compared with this. Born with a genetic condition that left him with almost no muscle control, his life is dependent on a ventilator puffing air into his lungs every three seconds. An attempt to add one second to that cycle nearly killed him. Three drugs that might have alleviated his condition failed to make any appreciable improvement. This was an important case because it is the first time a judge has been asked to rule against the wishes of a parent whose child does not have brain damage.

The mother agreed with the medical team in the paediatric intensive care unit (PICU), where the boy has lived since he was one hour old, that her son faced a life of intolerable pain and his life-support machine should be turned off. Increasing awareness of the hopelessness of his situation, combined with his inability to communicate distress, would make his plight even more unbearable as he matured, argued the NHS trust.

By contrast, the father, separated from the mother, testified that his son responded to him and could be brought home if he was given a tracheostomy to help his breathing. It was only when the father’s main medical witness visited the child in hospital last weekend and decided the procedure was not advisable that the father gave up his fight. Both parents sobbed as his decision to abandon the case was handed to the judge.

The case, in which there were fundamental differences of opinion not only between the parents but also among medical experts, shows just how difficult these decisions are. They also raise a series of ethical issues.

For those with religious convictions, they pose questions about how to define the principle of sanctity of life and where to draw the line on life-saving intervention. They question the absolutism of medical opinion and whether a mother’s wish outweighs that of a father. A lesser issue, but one likely to muddy the waters increasingly, is about the cost to the public purse not only in intensive care costs and nursing but also social care and endless operations.

Frequently, the biggest difference of opinion is between parents who seize on any spark of life and medical professionals who see a tiny child struggling with little prospect of improvement. Both perspectives can have the effect of distorting lenses. Who is best able to determine the quality of life of a severely disabled child?

Of course, the ideal answer is a joint decision taken after fully considering all options and possibilities, and thousands of such decisions are made every year. Only intractable disagreements end up in court, and it is right that they should. With technology and public opinion shifting so fast on such issues, it is important to test medical judgments periodically.

Their fallibility was demonstrated in the Charlotte Wyatt case, in which consultants gave the blind, deaf premature baby’s chances of survival as “approximately zero”, but she is now a five-year-old in foster care and can walk with a frame. The problem this creates for other parents is that it gives the impression it is right to extend life at all costs and inhibits them from asking the central question: for whom are we maintaining this life?

For Baby RB, there was no obvious answer. Once I interviewed a couple with a severely epileptic child. During the hour I was in the house, this poor boy had dozens of seizures, including one major one. The parents’ other two children clearly craved attention and looked malnourished. The house was chaotic. “This would drive me mad,” I told them frankly. “That happened to us years ago,” they admitted.

Julia Hollander, author of When the Bough Breaks about her struggle to care for a profoundly disabled baby, believes maternity hospitals are so neurotic about mortality statistics that even the sickest children are saved, particularly in the wake of the Charlotte Wyatt case. “But we don’t have the infrastructure to support the families,” she says.

With big cutbacks in social welfare budgets on the horizon, this situation is about to get much worse.

In the Baby RB case, the father’s change of heart spared the judge the need to decide the outcome. It would have contributed to the public debate if he had been obliged to weigh the arguments, though in his eloquent “words of endorsement”, he makes it clear he would have favoured the mother’s desire to spare her son further suffering.

It is a paradoxically life-affirming document (which can be read in full at www.bailii.org) in which he salutes the young parents for their exemplary devotion to their little boy, even though it cost them their relationship. He congratulates the parents and medical team for making RB’s life as “viable, comfortable and enjoyable and it could be”, but concludes that ultimately “it is just not in RB’s interests to contemplate a life for him outside the PICU” – or, indeed, inside it.

Every case is different. The parents of Charlotte Wyatt were right to fight for their daughter’s life, even if ultimately they did not have the capacity to care for her.

Equally, both of Baby RB’s parents deserve our sympathy and respect as they travel the final furlong of “this sad, sad journey”.