pure chance. More data are needed to clear up this
- The advantage to a child of being a member of a large or small family is a question of importance. In these days of birth control, the argument is frequently heard that large families are an evil of themselves, the children in them being handicapped by the excessive child-bearing of the mother. The statistics cited in support of this claim are drawn from the slums, where the families are marked by poverty and by physical and mental inferiority. It can easily be shown, by a study of more favored families, that the best children come from the large fraternities. In fact Alexander Graham Bell found evidence,52 in his investigation of the Hyde Family in America, that the families of 10 or more children were those which showed the greatest longevity (see Figs. 42 and 43). In this connection, longevity is of course a mark of vitality and physical fitness.
- The question of the effect of child-bearing on the mother is equally important, since exponents of birth control are urging that mothers should not bear more children than they desire. A. O. Powys' careful study53 of the admirable vital statistics of New South Wales showed that the mothers who lived longest were those who bore from five to seven children.
- The age at which men and women should marry has not yet been sufficiently determined, on biological grounds. Statistics so far compiled do not indicate that the age of the father has any direct influence on the character of the children, but the age of the mother undoubtedly exercises a strong influence on them. Thus it is now well established54 that infant mortality is lowest among the children of young mothers,—say from 20 to 25 years of age,—and that delay in child-bearing after