This raises a great many difficult issues. One response has been an objection to her apparently contradictory state of mind. She says she loves him dearly but "would rather have had an abortion than see him the way he is". A number of observers, especially those who are against abortion and some disabled-rights activists, protest that you cannot both love and value a person and wish they had never been born. They talk in terms of "genocide" of the less than perfect.
But Christina's case rests on the time when she was given the ultra-sound test and her son did not exist as a person to be loved, only as a potential person. At that stage, she says, had she been faced with the agonising news, she would have made the decision to abort - but that does not devalue her protective love for her child now he is born.
Most mothers confronted with news that their baby will be severely abnormal choose to have it aborted. Most mothers faced with the unexpected birth of a handicapped child love it as much as any other. However, the chance to know whether a foetus may be badly disabled is one of the greatest blessings of modern medicine. After all, the knowledge is optional - women can chose not to know.
The official figures tell the story: in 1982, 1,016 babies were born with severe abnormalities of the central nervous system: spina bifida, anencephaly, or hydrocephalus. That represented 16.1 per 10,000 births. Ten years later, the number of babies born with these devastating conditions had dropped to one quarter of that number, just 4.6 per 10,000 births, mainly because screening gave women the chance to chose abortion.
But all too quickly modern miracles, such as ante-natal screening, turn into "rights" and patients who fail to get as much benefit out of them as they feel they should turn litigious. Where once Christina O'Sullivan would have accepted her fate as horrible bad luck, now she has found someone to blame. The hospital admits that her son's condition could have been diagnosed from the ultrasound test she had, but it was not detected. She feels entitled to sue Northwick Park because she is a single mother who needs the money to care for him.
She is not the first - there have been a clutch of such cases. The hospital's lawyers say that most have failed, though some parents have won substantial damages. Legally these cases turn on an odd point of law. If a child has cerebral palsy because of the negligence of a doctor's clumsy delivery at the birth, then the child can sue for its pain, suffering and loss of amenity. But in screening cases, the child cannot sue because it cannot argue in court that it should never have been born. Instead, its parents sue for the cost of bringing up the child, which will be considerably less than the huge sums sometimes paid out for cerebral palsy caused by negligence.
The relatively new art of ante-natal testing has given rise to a plethora of litigation. Perversely, the more expert the doctors become and the better they become at detecting abnormalities, the more vulnerable they are to law suits when they fail - although nearly every medical test will give some false negative or false positive results.
Take Carol Anderson, for example. She claims she was told after an ultrasound scan that her child had severe water on the brain, or hydrocephaly. "When I was 17 weeks pregnant, they strongly advised me to terminate," she says. "But I wouldn't. I am a Catholic and I am against abortion. I went through my pregnancy believing I was carrying a badly handicapped baby, but when she was born she was perfect. If I had listened to what they said, she wouldn't be here now." So she started proceedings against the hospital. What for? "For the stress I suffered," she says.
Then there are the tragic cases of women told they are carrying a handicapped child, who go through with the abortion only to find that the child was, in fact, healthy. A high-profile case last month involved a baby who lived for 45 minutes after it was aborted following tests indicating it was abnormal. The pathologist told the coroner that the child was normal, so recorded a new verdict: death by legal termination.
In another case, Karen and Mark Southwell are suing the Princess Anne Hospital in Southampton for advising them to abort a foetus they now believe would have turned out to be healthy. (The hospital, as is often the case, claims the baby would have been born severely abnormal.) Some people will be more horrified by the idea of aborting a healthy child, while others will regard having an unwanted handicapped child as far worse. Either way, getting the wrong answer causes terrible grief. However, the total sum of suffering was far worse in the days before ultrasound was invented.
So how accurate are these ante-natal screening programmes? Dr Henry Irving, president of the British Medical Ultrasound Society, gives the rather startling reply that no one knows; there are no national figures. Various surveys have been carried out by some regions on their own results, but there is no national benchmark for accuracy. Nor is there any nationally agreed method of testing - some areas still use AFP blood tests, others only use ultrasound. Some hospitals have excellent new equipment, while others do not.
Doctors, says Dr Irving, will always tell patients what they consider the risk of abnormality to be: "They may say they think that there is a 50-50 chance, or a virtually 100 per cent chance, but they will base it on their own local experience, using their own equipment, not on any national rating." This may come as something of a shock to those who imagine they are part of a national screening system.
But the most difficult aspect of Christina O'Sullivan's case concerns her attitude towards the NHS. Increasingly patients seek someone to blame, knowing they may win substantial damages, dazzled by headlines about big pay-outs - though only 12 per cent of cases actually succeed. Even so, the NHS is paying out vast, escalating sums - and ambulance-chasing lawyers are making millions out of legal-aid cases, touting for business with posters in hospital emergency rooms asking: "Do you have a claim?"
In the lottery of life, some patients can clean up, and others can't. The law multiplies nature's own injustice. The family of a child suffering from cerebral palsy may do very well, while a child living next door with identical needs but no one to blame may get nothing. As a way of paying state money to care for disabled children, it makes no sense.
If Christina O'Sullivan gets a large sum, what general good does that serve? The law may keep the NHS on its toes, but the culture of litigation drains its resources, makes doctors practice defensive medicine and turns every medical advancement into a new chance to sue.Reuse content