[T]he European "let's stop at one" approach to childbearing really is well-calculated to maximize a certain kind of parental well-being, narrowly defined. Of course, it's also calculated to seriously diminish the "subjective well-being" of all the second and third children who don't get conceived because their parents decided it wasn't worth the trouble. And while the theory that parents have children "either for the benefit of the firstborn or because they reason that if the first child made them happy, the second one will, too" may be true in many or even most cases, it also reflects a certain degree of deplorable solipsism. The chief reason parents should take on the trouble of conceiving and raising a child is that the child is a good in and of itself - one of the greatest goods there is, in fact, in any moral scheme worth considering - not because they think that it will make them or their already-existing offspring happier.Okay, so when does birth control stop being solipsistic? If each additional child is a good in and of itself and failing to reproduce further is a serious (infinite) reduction in the subjective well-being of unconceived, yet somehow morally relevant, children, doesn't his argument in fact imply that we should go back to the old days of birthing until you dropped? If the happiness of the parents and of any currently-extant children is irrelevant, then you should never stop having children. I know in some faith traditions this is indeed the position, but his argument as presented invokes philosophy, not faith. In any event, deprioritization of the happiness of real, living humans and advocacy of unlimited childbearing is exactly the kind of thinking that can lead to horrible tragedy for some and a drastically degraded standard of living for others.
If Mr. Douthat's wife doesn't have at least one child every two years from their marriage to the onset of menopause, I call shenanigans.