One of the major blind spots conservatives have regarding family size is the oddly egalitarian idea that all children are basically the same and will turn out well (read: better than the children of their ideological opponents) no matter how much or how little you do for them beyond the basics. That, therefore, one should pop ’em out like pez because really, they just need extremely cheap food, some thrift-store clothes and can be put to sleep anywhere with a roof over it and anything more is just “nice to have”. But children are not all the same. To use an obvious example, a Down’s syndrome child will need very different resources and time than a neurologically and physically “normal” child. To use a less obvious example, there are babies that don’t mind if Mom pops into another room for an hour and will be very relaxed and let her take care of other little tasks that whole time, while other babies freak out if Mom just goes around the nearest corner for ten seconds. Those two babies grow up into children with very different social and interaction needs.
More to the point, the subtext of the endless refrains about how little children need elides the reality that if you have something like a Temple Grandin on your hands, that kid will need much and the price is very likely to include not many more or even any more children. She is an extreme and remarkable example, but there’s many other situations where it doesn’t serve the children or child you have already to keep adding more to the mix. Children can and do “get lost” in larger families and sometimes it will still all work out, but in a society where there are not tons and tons of other women around to help out, each individual mother has less reserve for additional children even if she is of the “rack and stack in one corner of our shack, feed ’em beans and rice til 18 and dress them only in castoffs” school of thought. This isn’t about coddling or helicoptering children, it’s about being able to meet the non-physical needs that children have effectively. And that’s hard to do when legal regulations mean having to purchase from among a short list of expensive vehicles in order to have more than three kids since most of America isn’t “walkable”. Or when the costs of “walkable” neighborhoods are so high that the household income has to be top 20% to even rent in one. Or when it’s a full time job just coordinating educational needs for each successive child.
The numbers don’t lie. There’s a reason very few people have that fifth or sixth child. I wish more women could, but we’d have to live in a pretty different world for that to happen.