Covering All The Angles

In writing up it's gay marriage legislation the government has covered all the angles:

It also prevents same-sex couples who are closely related from marrying, as federal legislation already does for opposite-sex couples.

Angry in the Great White North says what I wish really didn't need saying:

Why? Is the worry that the children born of that union will be idiots? Will it be OK for gay male third cousins to marry, but not gay male first cousins? Um, who are the idiots here?

One day someone is going to challenge this on the basis that it makes no biological sense. A pair of spinster sisters living together in their old age looking to get some benefits that come from marriage, such as the automatic ability to act with power of attorney in the case of illness, or automatic property rights. They will argue that they have a committed emotional relationship, cohabitate, and take care of each other's needs. Why then can they not enjoy the same benefits as other couples in the same situation? Why is it that they are being discriminated against simply because they are related? There is no basis for the discrimination. There are no potential children who might have genetic defects.

Indeed.