A few months back British Prime Minister David Cameron declared himself in favour of same-sex marriage because encouraging commitment is a conservative thing to do in his view.

Around the time he said that, Douglas Murray writing in The Spectator agreed. But his article was most noteworthy for what it left out.

The article has been praised as a slam-dunk argument in favour of same-sex marriage. But nowhere in it does Murray offer a definition of marriage that warrants it being given special social recognition and support above and beyond that given to any other form of committed relationship.

Even more importantly, he gives no consideration to what kind of family, if any, generally provides the best outcomes for children.

Indeed, children are mentioned in his article only to be dismissed from consideration because, as he tell us, not all heterosexual couples have children. This is telling. Marriage, to Murray, is mostly about adults.

But while not all married men and women have children, all children have a mother and father. What, if anything, should we do about this?

Should it be a matter of supreme indifference whether children are raised by the two people who bring them into the world?

To date, we have always said it is not a matter of indifference. We have said children ought to be raised by their natural parents and so we have encouraged this through creating the institution of marriage and giving it special recognition and support.

By leaving children out of the equation altogether Murray critically weakens his argument. If children are not the chief reason for giving marriage special support, then what is? Again, he doesn’t say.

Of course, there are same-sex marriage advocates who do include children in their argument. They say some same-sex couples have children (always with outside help needless to say), and this is true. But while Murray leaves children out of his argument, these other advocates for same-sex marriage insist that motherhood and fatherhood are of no special value.

Therefore they, like Murray, are supremely indifferent as to whether children are cared for by their own biological parents, or not, and this critically undermines their argument as well because no responsible society can be indifferent to such a thing.

But whatever else may be said about the issue, this much is certain; it is not in the least conservative to redefine in such a radical way the most vital social institution of all.

(Matthew Parris, who is gay himself, wrote something of a response to the Murray piece for The Spectator. Interestingly, he’s not entirely sure we can so easily dismiss from consideration a child’s need for a mother and a father. It is worth a read).