The Tsimane are hunter-gatherers of Bolivia who live in small isolated communities in the Amazonian rainforest along the Maniqui River. They have little by way of goods, and certainly none of those we call status goods., and thus they can easily raise their children — nine of them per family on average! They’re obviously highly successful survivors and, consequently, spill over into larger villages and towns along the river.
There, you might expect that they spend their earnings more evenly on family needs. Instead, it’s skewed towards status goods such as a wrist watch for the father or an expensive fashionable satchel for the children who go to school. As a consequence of this, it’s not surprising that their family sizes go down to four or five children when they live in villages and the three or four in the towns. When they finally settle in cities they’ll probably go down to two children per family or less because more status goods will be affordable .
This is a useful parable of modern parents in the bulk (80%) of the populations in most advanced European countries. Their children are now well below the replacement figure of two per woman. Not so the upper middle-classes (20%). They can afford all the status goods, in(often two!) and are now beginning to reverse the trend and are now heading back to replacements levels of children. This applies to America, too.