As long ago as 1971, a professor of demography at the University of California came to the conclusion that people's attitudes to childbearing are shaped by government and media propaganda, but their ideal number of children is always different from the number they actually have.
早在一九七一年，加州大學人口學教授就曾下過一個結論：生育的價值觀念是政府和傳媒宣傳的結果，然而理想子女數永遠與實際生育數有所差距。