Could it be that the growth of the population and the GDP has a common cause like advances in technology and medicine?
Why is the conclusion of the article more kids equals higher GDP and not the other way around.
Why do kids mean more economic growth? Current thinking is that of Oded Galor.[3] More people, more ideas, so more one-in-a-billion great ideas that improve everyboy's lives.
1. Energy and the English Industrial Revolution https://www.cambridge.org/core/books/energy-and-the-english-...
2. Ayres and Warr 2005, "Accounting for Growth: The Role of Physical Work" (pdf) http://113.212.161.150/elibrary/Library/Structural_Change/Ay...