Speaking on the proposed Civil Partnership Bill, Cardinal Sean Brady has stressed the importance of providing children with an "ideal environment" in which to grow.
But the real problem with the legislation as it stands is that it denies that environment to the children of same-sex couples. It undermines their right to a family.
Adoption is a children's rights issue and not an issue of the human rights of the adults who parent them. Nobody has the 'right' to adopt. Adoption must only be considered from the perspective of the rights of children. Children are not objects to be acquired by adults.
Gay people can already adopt in Ireland and have done so. There is no restriction on adoption in this State based on sexual orientation. But a gay couple cannot jointly adopt a child. This is not because they are gay. It is because they are unmarried. An unmarried couple, gay or straight, cannot jointly adopt either. But a straight couple can choose to get married. They can then jointly adopt a child. This is a choice denied to gay couples here but not to couples in the North.
In Europe, joint or second parent adoption by same-sex partners currently exists in the Netherlands, Spain, Belgium, Sweden, Denmark, Germany and Britain.
For me, the whole issue raises a number of questions.
Why is it okay for a gay person to adopt a child by him or herself but not to jointly adopt a child as part of a couple in a loving relationship? Why is it acceptable that a gay couple can raise a child together and give that child a loving family home, but not for the child to have a legal, secure relationship with both parents?
And, perhaps most importantly, why should the children of gay couples have inferior rights to the children of a married, heterosexual couple? Is that truly in the best interests of the child? Will this create an "ideal environment" for those children? In all the speeches and arguments on this issue, I have never seen those who are arguing against equality answer any of these questions. I've never even seen them try.
How can we in conscience allow the denial of the rights of children cared for by same-sex parents to be deliberately written into Irish law?
The issue at the heart of Minister Ahern's proposed legislation is not gay marriage or 'gay' adoption. It is discrimination. It is saying that the right to marry only applies to some people and not to others. But that's not true.
The right to marry is contained in Article 16 of the Universal Declaration of Human Rights and in Article 23 of the International Covenant on Civil and Political Rights.
Both treaties have very strong anti-discrimination clauses that make it crystal clear that the rights contained in them apply to all people, regardless of their status.
This was reiterated by the 1994 decision of the UN Human Rights Committee, charged with interpreting the ICCPR, in Toonen v Australia, which found that sexual orientation was a protected status in human rights law, the same as race or gender.
So let us be very clear on this. Refusing to allow a couple to marry because they are gay is a violation of their human rights.
Opponents of equality try to deny marriage rights to gay couples by arguing that marriage is about children, about creating and supporting secure families for children. But then these same people oppose extending the same security and care to children parented by same-sex couples as other children.
The argument is so illogical it seems to be based on denying the very existence of children parented by same-sex couples. Surely we have learned the cost of denying rights and protections to any particular group of children?
Some commentators, and Minister Ahern seems to agree with them, have made the argument that Ireland is not ready for equality. Thing is, the Irish people themselves seem to disagree.
According to a Lansdowne survey carried out for Marriage Equality earlier this year, 81pc of Irish people believe that everyone living in Ireland should receive equal treatment from the state regardless of whether they are lesbian, straight or gay.
Significantly, 75pc believed that the children of same-sex couples should have the same family rights as other children.
Six out of 10 believe that denying marriage to lesbians and gay men is an act of discrimination.
Marriage is a fundamental human right to which we are all, gay and straight, entitled. Those arguing against equality are profoundly out of touch with mainstream Irish opinion.
Maybe it's now time that they caught up.