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Swedish Early Separated Twins: Identification and Characterization

Published online by Cambridge University Press:  01 August 2014

N.L. Pedersen ,
L. Friberg ,
B. Floderus-Myrhed ,
G.E. McClearn  and
R. Plomin
N.L. Pedersen*
Affiliation:
Department of Environmental Hygiene, The Karolinska Institute, Stockholm College of Human Development, The Pennsylvania State University, University Park
L. Friberg
Affiliation:
Department of Environmental Hygiene, The Karolinska Institute, Stockholm
B. Floderus-Myrhed
Affiliation:
Department of Environmental Hygiene, The Karolinska Institute, Stockholm
G.E. McClearn
Affiliation:
College of Human Development, The Pennsylvania State University, University Park
R. Plomin
Affiliation:
Institute for Behavioral Genetics, University of Colorado, Boulder
*
Department of Environmental Hygiene, The Karolinska Institute, Box 60400, S-104 01 Stockholm, Sweden

Abstract

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A sample of twins separated early in life has been identified in the Swedish Twin Registry. When the registry was compiled in 1961 (old cohort) and 1973 (young cohort), one or both members of 961 pairs indicated that they were separated by the age of 10. In May 1979, both members of 698 pairs were alive and were sent a questionnaire concerning the circumstances of separation. Items included reasons and timing of separation, biological relatedness of rearing parents, degree of contact after separation (including whether they lived in the same area, attended the same school, or lived together again), rough measures of selective placement, and current frequency of contact. An attempt was then made to categorize the pairs based on degree of separation. A total of 257 pairs met the criteria: rearing parents of one twin biologically unrelated to rearing parents of the cotwin, twins not living together again after separation, and contact after separation a few times a year or less. As much as 50% were separated by their first birthday, and 80% by the age of five. Various data from the twin registry are presented describing the entire sample of early separated twins as compared to a matched sample of twins reared together.

Keywords

Twins reared apartTwin registry
Type
Twins Reared Apart
Information
Acta geneticae medicae et gemellologiae: twin research , Volume 33 , Issue 2 , April 1984 , pp. 243 - 250
Copyright
Copyright © The International Society for Twin Studies 1984

References

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