William Binchy (Opinion, May 12th) mistakenly attributes three constitutional changes to the marriage referendum.

He claims that the referendum would apply to gay unions a currently existing constitutional presumption that – all other things being equal – the welfare of children is best advanced by being reared in a home with a mother and father married to each other. This presumption no longer exists.

Article 42A.4.1 provides that in the resolution of all proceedings concerning the adoption, guardianship or custody of, or access to, any child, the best interests of the child shall be the paramount consideration. These decisions must be made on the basis of the child’s best interests, not the marital status of parents. Therefore, allowing gay people to marry will have no effect on adoption, guardianship or custody decisions.

Binchy also claims that the amendment would limit regulation of surrogacy by the Oireachtas. He presents an apparently simple deduction from a rule. Married couples have a right to procreate. Therefore, gay male married couples, who cannot procreate naturally, have a right to access surrogacy. There are several problems with this analysis, however.

First, the right to procreate is not absolute. Second, the courts have never held that the right to procreate includes the right to access assisted human reproduction (AHR) involving donated eggs, sperm or gametes. Third, the courts have held that the regulation of AHR, due to its extreme sensitivity, is a matter for the Oireachtas. The surrogacy argument therefore ignores the parameters of the constitutional right on which it relies.

Finally, Binchy claims the referendum may undermine freedom of religion: religious organisations involved in marriage guidance and child welfare might be required to respect marriage equality; churches might not be allowed to register only opposite-sex marriages; school curriculums might have to support the normative premises of same-sex marriage.These premonitions take no account of the existing constitutional position on freedom of religion. The courts have consistently allowed the Oireachtas restrict equality rights to protect religious freedom rights. The addition of equal access to marriage will not change this calculus.

Sense of déjà vu

Citizens understandably want to know what the effects of any constitutional change will be. Only then can we make an informed choice about whether the change is desirable. Assaulted by a cacophony of voices, however, it can be difficult for voters to come to their own view on the likely effects of a referendum.

Three general observations are worth bearing in mind when assessing the claims made by each side in any referendum.

First, the courts have interpreted constitutional amendments as solutions to the pre-existing issue that they were promoted to address. For instance, although the pro-life amendment has been given strong force in the abortion context, the courts have refused to apply it outside that context (for instance, to AHR).

Second, constitutional law is not about the application of standalone rules or propositions. The Constitution attempts to balance potentially competing values. Voters should be sceptical of arguments that rely on just one provision to claim results that are not at all obvious on the face of that provision. Such arguments usually overlook competing constitutional provisions.

Third, the Irish courts have interpreted the Constitution in a manner that allows the Oireachtas great latitude in balancing competing values. Voters should be wary of arguments that claim the freedom of the Oireachtas will be restricted. These arguments usually take no account of the deeply embedded culture of judicial deference that dominates Irish constitutional law.

This referendum, if passed, would have two effects. Most obviously, gay people could get married. Related to this, the Oireachtas would no longer be able, solely on the ground that they are of the same sex, to discriminate against gay couples.

Change vs continuity

Prof Oran Doyle is head of the school of law in Trinity College Dublin