I was just perusing an older copy of Gilbert Magazine, from whence I get most of my G.K. gold, and found this gem of Chesterton answering a letter to the editor when he was editor of his own magazine G.K.'s Weekly.
"Dear Mr. Chesterton,
You seem to support the Catholic notion that the chief object of marriage is the procreation of children. It is the typical masculine and mediaeval argument, smacking of the stud farm. You apparently think nothing of nobler aspect of love and sex.
Dear Mr. Herbert,
Well, Catholics will not resent being called masculine and are used to being called mediaeval. But what strikes me as truly extraordinary is the implication that there is something low about the objective being the birth of a child. Whereas it is obvious that this great natural miracle is the one creative, imaginative and disinterested part of the whole business. The creation of a new creature, not ourselves, of a new conscious center, of a new and independent focus of experience and enjoyment, is an immeasurably more grand and godlike act even than a real love affair; how much more superior to a momentary physical satisfaction. If creating another self is not noble, why is pure self-indulgence nobler?
I think that last line is the most badass response to this oft asked question I've ever heard!