When both Japan and the United States reported the lowest birth numbers since they began keeping records, the news made headlines. But the implications for schools in their respective countries have been given short shrift. With preschool just a few years away, that's an unfortunate oversight.

According to a survey by the Health, Labor and Welfare Ministry, the number of infants born in 2016 fell below 1 million for the first time since 1899. That represented a drop of about 25,000 from the previous year. The all-time high was 2.7 million registered in 1949.

The picture in the U.S. was equally startling. According to the Centers for Disease Control and Prevention, the U.S. birthrate fell to the lowest point since record-keeping began more than a century ago, with 62.3 births per 1,000 women. California's birthrate also dropped to its lowest level ever, with 12.42 births per 1,000. The closest the state came to that rate was during the Great Depression, when it hit 12.6 per 1,000 in 1933.