Japan’s birth rate has crashed to the point they sell more depends than diapers.
The US has a fertility rate of 1.87, which is 142nd, just behind Sweden. The US life expectancy is 79.68 years, which is 43rd in the world.
Japan has 0 migrant(s)/1,000 population (2015 est.), which is 93rd in the world. So does South Korea. The US has 3.86 migrant(s)/1,000 population (2015 est.), 34th in the world.
I would rather have more people wearing depends than a growing underclass wearing more and more diapers. By 2019, half of the children 18 and under will be minorities as classified by the USG; and by 2043 non-Hispanic whites will be just half the population, and 43% by 2060.