As well, people who have children typically have them in their 20s and 30s. Family size grows, on average, peaking in one's late 30s or early 40s. So the connection between family size and income is indirect, but another variable, age, plays an important role. None of this tells us what to expect about the childbearing propensities of poor as against non-poor families. And this is exactly what the evidence shows.
Poor families have more children and have more young children in particular, than non-poor families.
However, the average age of the head of a poor family is 7 to 8 years younger than heads of non-poor families, and is closer to the age at which family size peaks. So, to do a proper comparison, it is important to look at heads of poor and non-poor families that are at about the same age. Table 1 displays the number of children by poverty status while using comparable age ranges for the heads of the families for 1995. What the table shows is that poor families with only the very youngest heads have more children than their non-poor contemporaries, and even then, the margin is very small. Clearly, there is no evidence here to suggest that, as a group, poor families have more children.