Children can't be compared to goods. There's biological things at worth beyond self interest. That is to say, people want children, even though its not in their self interest.
I'd posit, if you were to try to assign children a status as a good in a wealthy culture, they'd be a luxury good. They cost a great deal, are effectively useless, but still desired.
<i>That is to say, people want children, even though its not in their self interest.</i>
It certainly isn't in the children's interest either, because they can't be benefited by being brought into existence (they are not waiting in some pre-existence limbo wishing to become existent).
I'd posit, if you were to try to assign children a status as a good in a wealthy culture, they'd be a luxury good. They cost a great deal, are effectively useless, but still desired.