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The Secular Decline in Dizygotic Twinning Rates in Italy

Published online by Cambridge University Press:  01 August 2014

William H. James
William H. James*
Affiliation:
The Galton Laboratory, Department of Human Genetics and Biometry, University College, London, Great Britain
*
The Galton Laboratory, Department of Human Genetics and Biometry, University College, 4 Stephenson Way, London NW1 2HE, Great Britain

Abstract

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It is shown that the recent secular decline in DZ twinning rates in Italy was not solely due to secular changes in birth order or maternal age.

The extent of the decline differed in different maternal age-parity categories. It seemed to be greater in younger women than older ones for constant parity. The data gave no clear support to the suggestion that the decline is associated with social class.

It seems that this secular decline in Italy has not been greatly affected by the use of ovulation-inducing drugs.

Type
Research Article
Information
Acta geneticae medicae et gemellologiae: twin research , Volume 24 , Issue 1-2 , January 1975 , pp. 9 - 14
Copyright
Copyright © The International Society for Twin Studies 1975

References

REFERENCES

Butler, N.R., Bonham, D.G. 1963. Perinatal Mortality. London: Livingstone.Google Scholar
Heuser, R.L. 1967. Multiple Births, U.S. 1964. National Center for Health Statistics. Washington, D.C.: U.S. Government Printing Office (PHS Publication No. 1000, Series 24, No. 14).Google Scholar
James, W.H. 1972. Secular changes in dizygotic twinning rates. J. Biosoc. Sci., 4: 427–434.Google Scholar
Jonckheere, A.R. 1954. A test of significance for the relation between m rankings and k ranked categories. Br. J. Statist. Psychol., 7: 93–100.CrossRefGoogle Scholar
MacGillivray, I. 1970. The changing incidence of twinning in Scotland 1939-68. Acta Genet. Med. Gemellol. (Roma), 19: 26–29.Google Scholar