"In this judgment I am concerned only with the loss that arises when the child's significant disabilities flow foreseeably from his or her unwanted conception. There may well be foreseeable incidents during the mother's pregnancy and the time leading up to the birth of the child from which the child's disabilities have flowed, but these will not in the ordinary way be effective to break the chain of causation. If, on the other hand, there is evidence that a child's disabilities, discernible at birth, were caused by some new intervening cause, then the difficult and interesting issues that may arise in such a case will have to be resolved by applying well-known principles of causation to the facts of the case before the court. A negligent surgeon should not, without more, be held liable for the economic consequences of the birth of a child with significant disabilities if the child's disabilities were brought about between conception and birth by some ultroneous cause (for which see Lord Wright in The Oropesa[1943] P 32 , 39). Similarly, the ordinary rules relating to contributory negligence will be applied in an appropriate case to limit recovery."
"Another question is when the disability must arise. [Counsel] argued that there was no rational cut-off point, as any manner of accidents and illnesses might foreseeably affect a child throughout his childhood. But that is part of the ordinary experience of childhood, in which such risks are always present, and the balance of advantage and disadvantage is deemed to be equal. The two serious contenders are conception and birth. The argument for conception is that this is when the major damage was caused, from which all else flows. This was what the defendant undertook to prevent. But there are at least two powerful arguments for birth. The first is that although conception is when the losses start, it is not when they end. The defendant also undertook to prevent pregnancy and childbirth. The normal principle is that all losses, past, present or future, foreseeably flowing from the tort, are recoverable. The second is that it is only when the child is born that the deemed benefits begin. And it is those deemed benefits which deny the claim in respect of the normal child. In practice, also, while it may be comparatively straightforward to distinguish between ante and post natal causes of disability, it will be harder to distinguish between ante and post conception causes. Further, the additional risks to mother and child (for example because of the mother's age or number of previous pregnancies) may be among the reasons for the sterilisation. I conclude that any disability arising from genetic causes or foreseeable events during pregnancy (such as rubella, spina bifida, or oxygen deprivation during pregnancy or childbirth) up until the child is born alive, and which are not novus actus interveniens, will suffice to found a claim."
"The short answer to [Mr Coghlan's] submission is that Megan is not and never has been a healthy child … At the time of her birth the infecting bacterium was sitting quietly on the surface of Megan's skin and/or gut. It was and remained asymptomatic for about 3½ weeks. The bacterium then entered her bloodstream and within 12-48 hours of entry symptoms of septicaemia followed by meningitis developed … In these circumstances Megan cannot, in my judgment, be treated as a healthy child …"