1. Educational attainment of same-sex and opposite-sex dizygotic twins
- Author
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Glen E. Duncan, Juan R. Ordoñana, Aline Jelenkovic, Esther Rebato, Amie E. Hwang, Wendy Cozen, Zengchang Pang, Weilong Li, Matthew Hotopf, Sisira Siribaddana, Leonie Helen Bogl, Dedra Buchwald, Robert F. Krueger, Brooke M. Huibregtse, Dorret I. Boomsma, Karri Silventoinen, Catherine Derom, Meike Bartels, Lucía Colodro-Conde, Ruth J. F. Loos, Catharina E. M. van Beijsterveldt, Athula Sumathipala, Jessica Tyler, Sarah E. Medland, Nicholas G. Martin, Fruhling Rijsdijk, Robert Vlietinck, Shandell Pahlen, Tracy L. Nelson, Kauko Heikkilä, Richard J. Rose, Anna K. Dahl Aslan, Thorkild I. A. Sørensen, Virgilia Toccaceli, Patrik K. E. Magnusson, Judy L. Silberg, John L. Hopper, Thomas M. Mack, Emanuela Medda, Grant W. Montgomery, Antti Latvala, Juan F. Sánchez-Romera, Qihua Tan, Dongfeng Zhang, Gonneke Willemsen, Matt McGue, Nancy L. Pedersen, Keith E. Whitfield, Jaakko Kaprio, Eero Vuoksimaa, Lorenza Nisticò, Christian Kandler, Hermine H. Maes, Robin P. Corley, Biological Psychology, APH - Health Behaviors & Chronic Diseases, APH - Mental Health, APH - Personalized Medicine, APH - Methodology, Helsinki Inequality Initiative (INEQ), Demography, Population Research Unit (PRU), Center for Population, Health and Society, Sociology, Department of Social Research (2010-2017), Institute for Molecular Medicine Finland, Clinicum, Department of Physiology, Department of Public Health, Cognitive and Brain Aging, Faculty Common Matters (Faculty of Medicine), Institute of Criminology and Legal Policy, Faculty Common Matters (Faculty of Education), and Technology Centre
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Male ,Twins ,Dizygotic twins ,Education ,Cohort Studies ,03 medical and health sciences ,Behavioral Neuroscience ,0302 clinical medicine ,Endocrinology ,5. Gender equality ,Sex differences in education ,RA0421 ,Twins, Dizygotic ,Humans ,Medicine ,Testosterone ,10. No inequality ,Birth Year ,Medicinsk genetik ,030304 developmental biology ,Sex Characteristics ,0303 health sciences ,Psykologi (exklusive tillämpad psykologi) ,Endocrine and Autonomic Systems ,business.industry ,Public Health, Global Health, Social Medicine and Epidemiology ,Testosterone (patch) ,Twin study ,Testosterone exposure ,Confidence interval ,Educational attainment ,Psychology (excluding Applied Psychology) ,Folkhälsovetenskap, global hälsa, socialmedicin och epidemiologi ,5141 Sociology ,Cohort ,Educational Status ,1182 Biochemistry, cell and molecular biology ,Female ,business ,Medical Genetics ,RA ,Twin testosterone transfer hypothesis ,SDG 4 - Quality Education ,030217 neurology & neurosurgery ,Demography - Abstract
Comparing twins from same- and opposite-sex pairs can provide information on potential sex differences in a variety of outcomes, including socioeconomic-related outcomes such as educational attainment. It has been suggested that this design can be applied to examine the putative role of intrauterine exposure to testosterone for educational attainment, but the evidence is still disputed. Thus, we established an international database of twin data from 11 countries with 88,290 individual dizygotic twins born over 100 years and tested for differences between twins from same- and opposite-sex dizygotic pairs in educational attainment. Effect sizes with 95% confidence intervals (CI) were estimated by linear regression models after adjusting for birth year and twin study cohort. In contrast to the hypothesis, no difference was found in women (β = −0.05 educational years, 95% CI −0.11, 0.02). However, men with a same-sex co-twin were slightly more educated than men having an opposite-sex co-twin (β = 0.14 educational years, 95% CI 0.07, 0.21). No consistent differences in effect sizes were found between individual twin study cohorts representing Europe, the USA, and Australia or over the cohorts born during the 20th century, during which period the sex differences in education reversed favoring women in the latest birth cohorts. Further, no interaction was found with maternal or paternal education. Our results contradict the hypothesis that there would be differences in the intrauterine testosterone levels between same-sex and opposite-sex female twins affecting education. Our findings in men may point to social dynamics within same-sex twin pairs that may benefit men in their educational careers. CC BY 4.0Correspondence Address: Silventoinen, K.; University of Helsinki, P.O. Box 18, Finland; email: karri.silventoinen@helsinki.fi© 2021 The Authors
- Published
- 2021
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