Some judgements, such as that of Glass JA of the NSW Court of Appeal clearly embraced a presumption of mothers winning custody.

The factor that tipped the balance in favour of the husband was the hostility of the mother to the father displayed in the presence of the child.

[1]: p 514–5  The mother argued that it was proper for an appellate court to exercise an independent discretion in respect of the facts found by the trial judge.

[1]: p 540  The judgement is critical of the views expressed by Glass JA in Epperson v Dampney,[7] noting there was nothing to support the asserted biological and genetic basis for the relationship.

They were also critical of the conclusions of the Family Court in Raby,[4] describing it as apparently based on sociological and psychological perceptions that could not be demonstrated to be true and on which expert opinion fluctuated.

[1]: p 528  The majority endorsed the middle ground in Ludlow v Hobbs,[5][8] that the mother's role was an important factor to be taken into account in the exercise of the Family Court's discretion.

[1]: p 528 Murphy J, one of the architects of the Family Law Act,[3] noted that there had been significant social change since the nineteenth century, particularly the movement of women into the workforce, accompanied by changed attitude to the roles of spouses, including their rights and duties in relation to the care of children.

Such presumptions should play only a very limited role in custody cases, stating "Even in a community of unchanging social conditions, hard and fast rules or presumptions, based only upon matters of common but not invariable experience, provide a poor basis for the assessment of human behaviour compared with detailed investigation of the individuals in question."

[1]: pp 517, 521–2 A second issue in the case was the proper function of an appellate court in considering a challenge to the exercise of judicial discretion, such as a decision in a custody matter.

The majority of the High Court rejected the proposition that a decision on custody was an inference to be drawn from the facts found by the trial judge, which an appellate court was in as good a position as the trial judge to draw and that Warren v Coombes,[9] had not changed the "settled principles of law" that applied to an appeal from a discretionary decision.

Stephen J allowing the appeal would involve yet another change in the custody of the girl in circumstances where the elapsed time of a year was more than a quarter of her life.

[1]: p 525  Murphy J would have remitted the matter to Evatt CJ to hear evidence as to the present circumstances of the child and the effect of another change in custody.

I am directed by authority to apply the common knowledge possessed by all citizens of the ordinary human nature of mothers.