The news that Tanaiste Eamon Gilmore wants to see legislation introduced that will allow same-sex couples to adopt before a referendum on same-sex marriage is instructive in a number of ways.

First, it tells us just how scared the Government is of the argument that children have a right to a mother and father. It does not want this argument to be part of the debate on redefining marriage.

According to Mr Gilmore’s spokesman, the Government regards adoption legislation as imperative in advance of a referendum on marriage.

“Any referendum that takes place will have to be about marriage equality and not about other issues,” the spokesman said.

In other words, they don’t want the referendum to be about children, because they know that is an argument they might well lose.

The statement also reveals just how much contempt this Government has for the Constitutional guarantee to protect marriage.

That guarantee pledges the State to guard with special care the position of marriage.  

But if the Government is prepared to extend the right to adopt to same-sex couples who are not married, what is left that is special about marriage? The Civil Partnership Act extended just about every other benefit of marriage to same-sex couples.  

At a more fundamental level, however, it shows that Mr Gilmore and co really don’t understand what the institution of marriage is for and why it receives special support.

As between two people, marriage is about love and companionship. But that is not the main reason why the State grants it recognition.  

The State, and prior to the State, the community, recognised marriage because only the union between a man and a woman can produce a child, and it is better for that child, and for society generally, if that child is raised by both of its biological parents, or failing that, by another man and woman.

There are plenty of loving relationships, and indeed romantic relationships, in which the State has precisely no interest. But introducing children into the equation changes things.

Gay and lesbians already parent children in some cases. Changes to the law on guardianship can take care of cases where the partner of the biological parent wishes to have legal relationship with that person’s child.

But it would be a very radical and unjust thing indeed for our laws to say, in effect, that biological parentage and motherhood and fatherhood have no special value at all and deserve no special recognition. That is exactly what they would say if same-sex adoption were legalised.