Heredity of twin births

Davenport, Charles Benedict (1920) Heredity of twin births. Proceedings of the Society for Experimental Biology and Medicine, 17. pp. 75-77.

DOI: 10.3181/00379727-17-44


About 1 per cent. of human births are twin births. However, there are certain families in which the proportion rises to 5, 10, or even 15 per cent. There can be little doubt then that, as in sheep, so in man, there are strains having a special tendency toward the production of twins. It is commonly believed that this tendency toward the production of twins must be wholly a maternal quality, depending upon the inherited tendency to double ovulation. The study of the heredity of twins is accompanied by certain difficulties, such as the fact that the occurrence of twins is frequently isolated, apparently haphazard, occurring perhaps in only one case in a fairly large fraternity, in which other representatives are single births. It will simplify the matter a little if we consider only those cases in which two or more sets of twins have arisen from a given mating. The study of twins is still further complicated by the fact that they are of two types, namely twins derived from a double ovulation and twins derived from a single ovulation, there being a subsequent fission or budding of the fertilized egg. Such single-egg twins are'easily distinguished clinically by being both enveloped in the same chorion. They are also always of the same sex. The statement that the mother alone determines the tendency to twins is not, however, supported by the facts. Of the births giving rise to the fraternities of twin-repeating mothers, 4.5 per cent, are twin births. Of the births giving rise to fraternities of twin-repeating fathers, 4.2 per cent are twin births. These figures depend upon 355 and 289 labors respectively. The sisters of twin-producing fathers have twins in 8.2 per cent. of labors, while the sisters of twin-producing mothers have twins in 5.5 per cent. of labors.

Item Type: Paper
Subjects: history > eugenics
CSHL Authors:
Communities: The Carnegie Institution Department of Genetics
Depositing User: Elizabeth Pessala
Date: 1920
Date Deposited: 05 May 2016 16:22
Last Modified: 21 Dec 2016 20:00

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