THE LOW SEX RATIO IN NEGRO BIRTHS. 



327 



STILL-BIRTHS IN THE U. S. REGISTRATION AREA IN RELATION TO 

 RACE AND NATIONALITY. 



In all the groups, as may be readily seen, the sex ratio for still- 

 births is remarkably high, and it is especially high for the Negro. 



Now for the second point, the relative proportion of still- 

 births in Negroes and whites. Calculating the ratio of still- 

 births to total births in the two races we find that the ratio is 

 over twice as high among the Negroes as among the whites, 

 namely 7.3 per cent, among the former and 3.5 per cent, among 

 the latter. Syphilis, which is a potent cause of still-births and 

 abortions, is very much more prevalent among the Negroes, and 

 doubtless accounts in no small measure for the high Negro rate of 

 ante-natal mortality. 



The facts of differential race and sex mortality in uterine life 

 enable us to explain the low sex ratio of live births among the 

 Negroes without assuming that there is any real racial difference 

 involved. In order to test this interpretation further I have 

 added the still-births and live-births together in the two races 

 and then calculated the sex ratios for total births. As would be 

 expected, the differences between the sex ratios of the two races 

 were reduced. For all whites combined the sex ratio became 

 106.72, and for the Negroes, 105.54. The inclusion even of the 

 confessedly incomplete data on still-births wipes out most of the 

 difference between the sex ratios of the two races. If complete 

 data on still-births were available, the differences between the 

 sex ratios would probably be reduced to insignificant proportions. 



