In demographics, one of the measures that is referred to is replacement level. Also related to the idea of Total Fertility rate (TFR) and something called sub-replacement fertility.
The basic idea is that the average couple 'needs' to have about 2.3 children in order to 'replace' themselves in a future population after they have gone. The reason why it is not just 2 is related to problems with fertility for some women, and also variations in the age at which women (or their partners) decide to start a family.
There's also something called the Tempo Effect, which is worth exploring further.
Thanks to Will Tuft for pointing me to this Guardian article which put a different perspective on David Beckham's recent addition to the family: Harper Seven.
In 1930, just one or two generations ago, the world's population stood at around two billion. Today it is around seven billion, and by 2050 it is projected to rise by a third to 9 billion.
As a starter image, you could use one which shows David Beckham's football boot which has the names of his children embroidered on it...
Comments