Front Matter

222 Autism and Exposure to Environmental Chemicals

4

4.5

3.5

3

2.5

2

1. 5

To tal

fertility ra

te (per women)

1

0.5

0

1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010

1960

4

3.5

3

European union

Japan

USA

Replacement level

2.5

2

1. 5

To tal

fertility ra

te (per women)

1

0.5

0

1965197019751980198519901995200020052010

(a)

(b)

Figure 7.18 (a) Total fertility rates of the European Union, Japan and the USA, 1960–2013.

The dotted line represents a fertility rate of 2.1, below which a population cannot be

sustained Source: Adapted from http://databank.worldbank.org/data/views/

variableselection/selectvariables.aspx?source=world‐development‐indicators. (b) Total

fertility rate of Denmark, 1901–2014. The dotted line represents a fertility rate of 2.1.

Note that a downwards trend in total fertility rate started long before introduction of the

contraceptive pill in the 1960s. Apparently the trend was interrupted by the First and

Second World Wars. Source: Adapted from Statistics Denmark. http://www.statistikbanken.

dk/statbank5a/default.asp?w=1600.