Impassioned calls for same-sex marriage have left some of our MPs perilously prone to well-intentioned confusion. Before they redefine a fundamental institution of human civilisation, our elected representatives would do well to consider why marriage exists at all.Greens Senator Sarah Hanson-Young has put forward a bill which would redefine the institution of marriage to include same-sex couples. The argument goes something like this: heterosexual couples have it, and because they have it, same-…
