So to continue your argument to its illogical conclusion only people who plan to, and actually do have children, therefore failure to have children would lead to the marriage being declared void.
Parents would be forbidden from separating or dying before their children reach adulthood and so on. All impossible premises that you seem to ignore.
Marriage is not owned by the church. They just want it to be.
As for social problems I wish the church was even as slightly concerned about priests who had non-consensual sex (i.e. rape/abuse) with children as they are about consenting adults who wish to formalise their relationship.
There are two simple ways to end this discussion:
1) Allow two consenting adults who are not already married and are not close family, to marry. Or.
2) Abolish the marriage act and not allow anybody to marry any more.
The church has repeatedly proven that they have no moral authority over the people, they like to tell us, "do as I say, not what I do".
We'd be a much better society without the church and religion imposing their will on us without contributing to society.
You raise a good point
HVR.
The church is meant to voice a moral authority here on earth. Unfortunately, there have been many egregious abuses throughout history, which have diminished that, which, any true Christian should be sorry for. And again, let us ignore the positive contributions for the moment. And you are confounding the different pockets of the church (and if you think about Margaret Court, she has nothing to do with the Roman Catholic church and the rape/abuse of children)
But this debate is not between a church and society. You will see throughout societies (irrespective of their judeo-Christian heritage or not - just look at Asia) , that marriage has traditionally been between a man and a woman. It just so happens, that leaders in the church are the easiest targets for abuse.
But the central question still remains: Is marriage defined as between a man and a woman (as it has for milienia, throughout different cultures and societies). And is this a question of absolute or relative morality?
If it is an issue of absolute mortality (absolute right and absolute wrong) then the debate is really the source of absolute morals.
If not, then this becomes an issue of relative morality (and really, then who are you to judge my morals?)
I happen to think that marriage being defined as between a man and a woman, a question of absolute morals (and as evidenced through common law, and by and large through time, through different cultures and societies).
But on your point to end the discussion: the simplest way (which appeals to the notion of relative morality) is
(i) Hold the plebiscite, and let the will of the people decide (and politically speaking, this will diminish greatly the chance of any reversal of any decision, through any future changes of government). But, cynical me thinks why a large part of the LGBT lobby does not want this, is that there is a high chance it gets voted down, leaving them with little ammunition to continue their militant tactics. Mind you, there are supporters of SSM that want this plebicite to happen, so it is not a uniform view across the LGBT community