another in fertility.

The delay in marriage, as studied in England, is so far apparently
slight; the mean age of marriage for all husbands in England has
increased from 28.43 in 1896 to 28.88 in 1909, and the mean age of all
wives from 26.21 in 1896 to 26.69 in 1909. This seems a very trifling
rate of progression. If, however, we look at the matter in another way
we find that there has been an extremely serious reduction in the number
of marriages between 15 to 20, normally the most fecund of all
age-periods. Between 1876 and 1880 (according to the Registrar-General's
Report for 1909) the proportion of minors in 1000 marriages in England
and Wales was 77.8 husbands and 217.0 wives. In 1909 it had fallen to
only 39.8 husbands and 137.7 wives. It has been held that this has not
greatly affected the decline in the birth-rate. Its tendency, however,
must be in that direction. It is true that Engelmann argued that delayed
marriages had no effect at all on the birth-rate. But it has been
clearly shown that as the age of marriage increases fecundity distinctly
diminishes.[119] This is illustrated by the specially elaborate statistics
of Scotland for 1855;[120] the number of women having children, that is,
the fecundity, was higher in the years 15 to 19, than at any subsequent
age-period, except 20 to 24, and the fact that the earliest age-group is
not absolutely highest is due to the presence of a number of immature
women. In New South Wales, Coghlan has shown that if the average number
of children is 3.6, then a woman marrying at 20 may expect to have five
children, a woman marrying at 28 three children, at 32 two children, and
at 37 one child. Newsholme and Stevenson, again, conclude that the
general law of decline of fertility with advancing age of the mother is
shown in various countries, and that in nearly all countries the mothers
aged 15 to 20 have the largest number of children; the chief exception
is in the case of some northern countries like Norway and Finland, where
women develop late, and there it is the mothers of 20 to 25 who have the
largest number of children.[121] The postponement in the age of marriage
during recent years is, however, so slight that it can only account for
a small part of the decline in the birth-rate; Coghlan calculates that
of unborn possible children in New South Wales the loss of only about
one-sixth is to be attributed to this cause. In London, however, Heron
considers that the recogniz