On the distribution of sex ratio in a family

Abstract

Although the distribution of sex ratio in each family, as obtained by the writer from the complete permanent domicile registers of Usigome ward, Tokyo, gave the same result as Koya's, that is, the frequency of families in which only male or female children are born, is much larger than that which may be expected from the probablity law, the writer is of opinion that the births of male and female children do not follow any particular law, but occur at random, the reason for the statistics pointing otherwise being due to the arbitrary ways in which births are at present registered by the authorities. © 1941, The Genetics Society of Japan. All rights reserved.