One public figure who has weighed into the debate is Amanda Vanstone, who was a minister in John Howard's Liberal Government.
It's another chance to look at the political beliefs of a high profile member of the right-wing party here in Australia.
Amanda Vanstone is known as a more socially liberal member of the party. So it's no surprise that she supports homosexual marriage. What is more surprising is the grounds on which she supports it. She argues:
Perhaps we need a reality check on what we think marriage really means. Opponents of gay marriage often argue that marriage is ''a union between a man and a woman, to the exclusion of all others, for life''.
It is not convincing. It is a triumph of hope over reality. Marriage long ago stopped being to the exclusion of all others and for life. If we don't care about those two elements being disregarded by so many, why should we care about the ''between a man and a woman'' part?
The idea that marriage has already lost its real meaning and that therefore there is nothing to lose in accepting homosexual marriage is not unusual. It was made by three columnists in the Melbourne papers today: Amanda Vanstone, Wendy Tuohy and Dennis Altman.
Tuohy's column is particularly interesting, as it basically says that there is nothing sacred left in the world-weary West and therefore marriage has become so watered down in meaning that it no longer makes sense to exclude gays.
I don't disagree that the meaning of marriage has been watered down. But there are two things to note about this argument. First, it's not a very good way to justify homosexual marriage. What is being suggested is that homosexual marriage would be incompatible in meaning with the original, intact, traditional meaning of marriage. But it is compatible, the argument goes, with the meaning that is left to a broken form of modern marriage. Isn't that really an acknowledgement that homosexual marriage does affect the meaning of marriage?
Second, it's a radical position for Amanda Vanstone to take. She doesn't find the idea that marriage is exclusive and for life to be "convincing". She has moved on to a model of marriage that is not exclusive and not for life. She describes this as a "reality check" on what marriage really means. So the meaning of marriage for her is radically open - except for one remaining, restraining principle.
She lost her father as a young child and she knows someone who has struggled with not knowing his biological father. So she seems to draw the line at creating families that do not have both a male and a female parent:
It is, in my view, in the best interest of every child that they have on a day-to-day basis both male and female parent role models and both male and female adult role models.
I agree with her and won't criticise her for holding this view. But it seems to be inconsistent with the earlier part of her argument. If we are going with a new meaning of marriage which is neither exclusive nor life-long, then families won't be as stable as previously. So more children, not less, will end up living without male and female parental role models.
How exactly does she expect children to have both male and female parental role models on a day-to-day basis in her new family order? If we have accepted, as a principle, that marriage is no longer to be faithful and no longer to be for life, then surely that will lead to more children living without one of their parents. And if the state endorses the idea of homosexual marriage, then surely that will lead to more children living with parents of just one sex.
If you want to try and hold the line somewhere in a liberal society, then it had better be a mighty strong line you are holding onto. But Vanstone's is weak. She has cut most of the way through it herself.
And I suppose this illustrates the difficulty of wanting to be socially liberal, whilst still believing in some kind of traditional standard in society. It's difficult to unleash the forces of "do whatever you will" and then add on "except for this". Standards can't be defended that way. They have to make sense within a larger framework of society. If you want children to be raised by parents of both sexes, then you ought to be defending marriage having the meaning of a faithful, lifetime commitment between a man and a woman.
But this is what Amanda Vanstone believes ought to be abandoned, or at least relegated to a few hold-out churches.