French government officials have long been known among Europeans for the special attention they give to the state of their population. In the first half of the nineteenth century, as Paris doubled in size and twice suffered the convulsions of popular revolution, civic leaders looked with alarm at what they deemed a dangerous population explosion. After defeat in the Franco-Prussian War in 1870, however, the falling birthrate generated widespread fears of cultural and national decline. In response, legislators promoted larger families and the view that a well-regulated family life was...