Familial excess of births of the same sex
Baumann, R.
Arch Rassen U Ges Biol 18(2): 152-164
1926
Document Number: 511859
New data were secured from the official birth register of Ludwigsburg, Wurttemberg, for 1866-1923. Records of 8477 unions, each producing 2 or more children (in all 19,275 girls and 20,028 boys), are included. The proportion of boys to girls among the brothers and sisters, of boys was 106.15:100, that of girls 101.66:100. The difference is about 6 times its probable error. The conclusion is that sex distribution of these families approaches a purely chance one, although a distinct deviation, without practical significance, exists. Discussion of other data on the subject is included.