Fig. 2. Proportions having at least one child by 5-year age group at marriage and estimated typical pattern. The populations (in descending order at age 35 to 39) are Germany, 14 village genealogies, marriages 1750-1899 ( solid circles ); England, family reconstitution of 16 rural parishes (mid-16th to early 19th centuries) by the Cambridge Group for the History of Population and Social Structure ( solid squares ); Ireland, 1911 census ( solid triangles ); typical pattern ( flat line ); England, family reconstruction for Quakers ( open circles ); Quebec, rural women born before 1876 ( open squares ); Scotland, 1911 census ( open circles ); and Quebec, 1946 census, rural women born before 1876-1885 ( open triangles ). (From Menken J, Trussell J, Larsen U: Age and infertility. Science 233:1389, 1986.)