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The Monozygotic Twinning Rate: Is It Really Constant?

Published online by Cambridge University Press:  01 August 2014

G. Allen*
Affiliation:
U.S. Public Health Service, Retired, Bethesda, Maryland
Z. Hrubec
Affiliation:
National Cancer Institute, U.S. Public Health Service, Bethesda, Maryland
*
9326 W. Parkhill Dr., Bethesda, MD 20814, USA

Abstract

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Weinberg's difference method, applied to twin birth statistics, usually shows a dependence of the MZ rate on maternal age, like a thin shadow of the DZ rate. Some of this MZ variation could be explained away by James' finding of more same-sex (SS) than opposite-sex (OS) DZ twins, the excess being mistakenly classified as MZ by Weinberg's assumption of equal numbers. By several methods one can extract a Constant value for the MZ rate and a Constant or nearly Constant value for the DZ SS/OS ratio, but these “constants” are actually arbitrary and they vary between populations.

Type
Research Article
Copyright
Copyright © The International Society for Twin Studies 1987

References

REFERENCES

1.Allen, G (1981): Errors of Weinberg's difference method. In Gedda, L, Parisi, P, Nance, WE (eds): Twin Research 3. Part A: Twin Biology and Multiple Pregnancy. New York: Alan R Liss, pp 7174.Google Scholar
2.Boklage, CE (1985): Interactions between opposite-sex dizygotic fetuses and the assumptions of Weinberg difference method epidemiology. Am J Hum Genet 37:591605.Google Scholar
3.Bulmer, MG (1970): The Biology of Twinning in Man. Oxford: Clarendon Press.Google Scholar
4.Heuser, RL (1967): Multiple Births, United States – 1964. Washington; US Government Printing Office (Public Health Service Publication No. 1000, Series 21, No. 14).Google Scholar
5.James, WH (1976): The possibility of a flaw underlying Weinberg's differential rule. Ann Hum Biol 3:549556.Google Scholar
6.James, WH (1984): Twins. N Engl J Med 311:58.Google Scholar
7.McArthur, N (1953): The frequency of monovular and binovulai twin births in Italy, 1949-1950. Acta Genet Med Gemellol 2:1117.CrossRefGoogle ScholarPubMed