The problem is, if the overall fertility rate stays at 1.7, then there will be no replacement for each pair of parents. Once the population peak passes, if there are no factors such as international migration, the population will show negative growth and then will radically decline.
問題是，如果婦女總生育率維持目前的一點七，即每對夫妻生不到兩個小孩來代替自己，人口高峰一過，在沒有國際移動等其他變數之下，人口將開始呈負成長，然後急速下降。