Other Factors.—Many other factors have been alleged to exercise an influence, greater or less, on masculinity at birth, among them being cross-breeding and illegitimacy. In each of these, the position must be held to be not proven. In 1915 in the United States birth registration area the children of mixed parentage showed a much lower masculinity than those of native or foreign parentage—while in New York the births for five years showed a higher masculinity for children of mixed par entage. In British Guiana, the masculinity of children of mixed parentage for the decade 1903-12 was lower than that of the East Indians or blacks, while in Rio de Janeiro from 1910-15 the ratios were whites 1,049, mulattos 979, blacks 999. It is probable that the effects of cross-breeding are determined by the nature of the cross. As for illegitimacy the evidence is also conflicting, but in the majority of countries the legitimate births show a greater ratio of males. To be of real value, however, the figures should relate not to the numbers born out of wedlock, but to those resulting from casual unions. Some proportion (often a consider able one) of the births classed as illegitimate is the result of unions which, though not recognized by the law or the Church, are, from the physiological point of view, marriages.
Sex-ratio at Death.—As at birth, it is a pretty general rule that the ratio of males at death is higher than that of females; indeed, the disparity in mortality is much more marked than in natality. In this case, however, the causes are by no means so obscure and doubtful as when dealing with masculinity at birth. Those of primary importance are the more persistent vitality of the female and the fact that the specially dangerous pursuits are mainly in the hands of males. A very simple proof of the former is the very marked disparity in deaths of males and females in the first few days of life, of the latter the disproportionate number of male deaths from external or violent causes. The ratio of male
to female deaths is not spread equally over the whole of life ; it is, generally speaking, very high in the first year and much lower at ages I to 5, while at ages 5 to 15 the ratio of female mortality is in most countries higher than that of males. As age advances the female advantage becomes more and more marked. It differs considerably from country to country. The following table gives the male and female death rates and the ratio of male deaths to 1,000 deaths of females in a number of countries for the trien nium 1920-22, the years being those around the last census taken, when the respective numbers of the sexes had been defi nitely ascertained. (Note: The data given is confined to eleven countries in which white predominate.) It will be seen that in Sweden alone the deaths among an equal number of males and females show a slight advantage on the male side, that in Denmark the sex mortality was equal, while in all the other countries the male mortality showed excess in varying degree. In England and Wales, Finland and Germany the excess is very heavy indeed. Going outside Europe, it may be mentioned that in Chile the ratio of male to female deaths in equal numbers for the same period was i,o6o, in Japan 978, in British India 1,082. In the United States for the year 1924 the ratio was 1,144, a figure almost identical with that shown for England and Wales in the foregoing table. It may be as well to say that the rates and ratios given in this section of this article are calculated on the census populations of the census taken at the end of 1920 or early in 1921. (S. DE J.)