Therefore, the state is entitled to hold the view which is espoused and evident from its laws.
The New York Times hailed the victory as putting Ireland at the "vanguard of social change".
Both male and female same-sex sexual activity is legal in the state.
Coincidentally, the task of signing the bill decriminalising male homosexual acts fell to the then President of Ireland, Mary Robinson, an outspoken defender of gay rights who as a barrister and Senior Counsel had represented Norris in his Supreme Court and European Court of Human Rights case.
Same-sex marriage is legal in Ireland, following approval of a referendum on which amended the Constitution of Ireland to provide that marriage is recognised irrespective of the sex of the partners.
Judge Mc Kechnie J noted that in Ireland it is crucial that parties to a marriage be of the opposite biological sex.