... according to the Archbishop of Canterbury...
I take it he means that there are sociological and logical reasons of the kind he identifies to oppose same-sex marriage:
The result is confusion. Marriage is abolished, redefined and recreated, being different and unequal for different categories. The new marriage of the Bill is an awkward shape with same gender and different gender categories scrunched into it, neither fitting well. The concept of marriage as a normative place for procreation is lost. The idea of marriage as covenant is diminished. The family in its normal sense, predating the state and as our base community of society – as we’ve already heard – is weakened. These points will be expanded on by others in the debate, I’m sure, including those from these benches.
For these and many other reasons, those of us in the churches and faith groups who are extremely hesitant about the Bill in many cases hold that view because we think that traditional marriage is a corner stone of society, and rather than adding a new and valued institution alongside it for same gender relationships, which I would personally strongly support to strengthen us all, this Bill weakens what exists and replaces it with a less good option that is neither equal nor effective. This is not a faith issue, although we are grateful for the attention that government and the other place have paid to issues of religious freedom – deeply grateful. But it is not, at heart, a faith issue; it is about the general social good. And so with much regret but entire conviction, I cannot support the Bill as it stands.