Americans just celebrated the birth of Christ 2,000 years ago. What we are celebrating a lot less these days is the birth of our own babies. In short, America’s fertility rate is in a free fall. Over a 60-year period between 1957 and 2017, fertility rates in the United States plummeted. About 11 percent fewer babies were born in America in 2017 (3,853,472) than in 1957 (4,316,233.) But drop is at the same time as the population in America doubled, meaning the fertility rate as measured by number of births per woman in the country has fallen by more than...