The decision in favour of two brothers in Co Donegal does not have fundamental implications for the status of foster children, according to family lawyers.
It was based on a legal doctrine called "legitimate expectation", which relates to circumstances in which a person acts against their own immediate interest in the reasonable expectation of a positive outcome.
Judge Matthew Deery said he was ruling in favour of the two brothers, the foster children of Mary and Paddy Boyle, under the doctrine of legitimate expectation. He said there was little doubt that Mr Boyle intended that both of them would, in the fullness of time, take benefit of the lands.
However, he pointed out that there should be some distinction in relation to people in long-term fostering arrangements that transcend just a year or two. Ms Marie Baker, a family lawyer in Cork, said the case which established the doctrine of legitimate expectation as a principle of Irish law was that involving the Derrynaflan chalice, where the farmer who found it gave it to the National Museum in the expectation of being recompensed.
She said Judge Deery appeared to say that the familial connection strengthened the brothers' reasonable expectation with regard to their parents' estate.
Ms Catherine Forde, who also specialises in family law, said that there could be a distinction between children fostered by the health board in return for payment and those who, to all intents and purposes, were adopted.