Marriage should be limited to unions of a man and a woman because they alone can “produce unplanned and unintended offspring,” opponents of gay marriage have told the Supreme Court.

By contrast, when same-sex couples decide to have children, “substantial advance planning is required,” said Paul D. Clement, a lawyer for House Republicans.

Lawyers defending California’s Proposition 8 and the federal Defense of Marriage Act want the high court to decide it is reasonable for the law to recognize only marriages between opposite-sex couples.

McKen sums it up nicely:

So in their world, the fact that gay couples put thought and effort into family planning is why they shouldn’t be allowed to marry, whereas accidents are a good excuse for being forced into matrimony.