This brief survey is enough to prove that the best educated young women (and to a less extent young men) of the United States, who for many reasons may be considered superior, are in many cases avoiding marriage altogether, and in other cases postponing it longer than is desirable. The women in the separate colleges of the East have the worst record in this respect, but that of the women graduates of some of the coeducational schools leaves much to be desired.
It is difficult to separate the causes which result in a postponement of marriage, from those that result in a total avoidance of marriage. To a large extent the causes are the same, and the result differs only in degree. The effect of absolute celibacy of superior people, from a eugenic point of view, is of course obvious to all, but the racial effect of postponement of marriage, even for a few years, is not always so clearly realized. The diagram in Fig. 36 may give a clearer appreciation of this situation.
Francis Galton clearly perceived the importance of this point, and attempted in several ways to arrive at a just idea of it. One of the most striking of his investigations is based on Dr. Duncan's statistics from a maternity hospital. Dividing the mothers into five-year groups, according to their age, and stating the median age of the group for the sake of simplicity, instead of giving the limits, he arrived at the following table:
| Age of mother at her marriage | Approximate average fertility |
|---|---|
| 17 | 9.00—6 × 1.5 |
| 22 | 7.50—5 × 1.5 |
| 27 | 6.00—4 × 1.5 |
| 32 | 4.50—3 × 1.5 |
which shows that the relative fertility of mothers married at the ages of 17, 22, 27 and 32, respectively, is as 6, 5, 4, and 3 approximately.
"The increase in population by a habit of early marriages," he adds, "is further augmented by the greater rapidity with which the generations