With thanks to Phil Gleeson for drawing my attention to O’Loughlin v McCallum  WADC 77 (available on Austlii), a wrongful birth claim in which breach of duty was admitted in respect of a failed sterilisation procedure. The Court was required to assess damages. The allowances were as follows:
General damages $20,000. It is noteworthy that at  the Court said “However, the fact of Ms O’Loughlin’s inability to participate in normal activities of caring for her children is compensable as a loss of amenities”.
Loss of earning capacity $20,000 including interest.
Costs of raising the child (who did not suffer disabilities) – for the past $25,116 and for the future $52,957, until age 18. The four oldest siblings ceased to be dependent on their parents before turning 18. There was no evidence of BK having particular needs that would distinguish him from his siblings ().
The defendant argued that the net present value of family assistance payments available to the parents should be offset from the costs of raising the child, however the Court did not accept that argument. At  the primary judge said “Legislative pursuit of these matters is not inconsistent with a legislative intention that Family Tax Benefit be retained by a recipient who may have rights of redress against others in connection with the cost of raising a child.”.
The primary judge commented on a gratuitous services claim, but on close reading this seems to be in respect of a need for such services by the mother, not by the child. The relevant passage is at :
Parts of the testimony of Ms O’Loughlin and Mr Smith suggest claims for damages for Mr Smith’s gratuitous care of Ms O’Loughlin and for his assuming her role in care of their children. The law does not admit of a claim for damages for Mr Smith’s ‘stepping into’ Ms O’Loughlin’s role and caring for their children. If supported by evidence, the claim for care of Ms O’Loughlin would be compensable in accordance with the principles established by the High Court in Griffiths v Kerkemeyer. However, there is insufficient evidence on the nature and extent of services Mr Smith provided to Ms O’Loughlin to make any assessment of damages.