Jonah, I don’t think that your first correspondent has it right. Expansive public retirement systems are a product of affluent societies. Women in affluent societies tend to have fewer children. Beyond a certain point, the phenomenon he describes is (mostly) a question of correlation – not causation. On the other point (“everyone, whether they have

children or not, contributes to the raising of the next generation”), your other, perturbed, readers are, of course, quite correct.