It’s children’s day in Japan and the Koinobori – or carp flags – are flying. (The Japanese see the carp as one who perseveres in the face of struggle – a good symbol for children to aspire to.)

But children’s day also reminds one of how precious children are in this country. I don’t mean precious in the sense of ‘highly esteemed’ or dear and beloved. I mean precious in the sense that children are increasingly a rare and valuable commodity. According to a list of countries by Total Fertility Rate, Japanese women of childbearing age are expected to produce an average of just  1.21 children. That puts Japan at number 223 on the list of 228, sharing the bottom of the fertility rankings with South Korea, Singapore, Republic of Taiwan and Macau. Prosperity (wealth) is usually blamed (or credited) for bringing on a low fertility rate. (The wealthy western European countries also have low fertility rates.) As a people become richer, they must devote a greater share of their resources to raising children. This is a paradox – it looks like a contradiction. You might think that wealthy people can afford to raise more children, but it turns out not to be the case. Sometimes we wonder why people in poorer societies have so many children. But in those societies, children are required to increase a family’s income.

I do notice at least one exception to the rule. Thailand – with GDP per capita of only $3916 – has a fertility rate of 1.65. That’s lower than such highly-developed economies as Denmark, Norway and the USA, which has a fertility rate of 2.05. Thailand’s next-door neighbor, Malaysia has a GDP per capita of $5155 – but it’s fertility rate is 2.95.

So… Obviously the answer is more complicated.

What are your favorite reasons for why fertility rates rise or fall?