{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,8]],"date-time":"2026-01-08T03:24:39Z","timestamp":1767842679603,"version":"3.49.0"},"reference-count":37,"publisher":"Oxford University Press (OUP)","issue":"7","license":[{"start":{"date-parts":[[2020,6,19]],"date-time":"2020-06-19T00:00:00Z","timestamp":1592524800000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by-nc\/4.0\/"}],"funder":[{"name":"European Union\u2019s Horizon 2020"},{"name":"Marie Sk\u0142odowska-Curie"},{"name":"PROTECTED","award":["722634"],"award-info":[{"award-number":["722634"]}]},{"name":"FREIA","award":["825100"],"award-info":[{"award-number":["825100"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2020,7,1]]},"abstract":"<jats:title>Abstract<\/jats:title>\n               <jats:sec>\n                  <jats:title>STUDY QUESTION<\/jats:title>\n                  <jats:p>Does having a male co-twin influence the female twin\u2019s reproductive outcomes?<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>SUMMARY ANSWER<\/jats:title>\n                  <jats:p>Women with a male co-twin had the same chances of being pregnant and having children compared to same-sex twin pairs.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>WHAT IS KNOWN ALREADY<\/jats:title>\n                  <jats:p>According to the twin testosterone transfer (TTT) hypothesis, in an opposite-sex twin pregnancy, testosterone transfer from the male to the female co-twin occurs. A large body of literature supports the negative impact of prenatal testosterone exposure on female\u2019s reproductive health in animal models; however, evidence from human studies remains controversial.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>STUDY DESIGN, SIZE, DURATION<\/jats:title>\n                  <jats:p>This cohort study included all dizygotic female twins in the Aberdeen Maternity and Neonatal Databank (Scotland) born before 1 January 1979. The 317 eligible women were followed up for 40 years for any pregnancies and the outcome of those pregnancies recorded in the same database.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>PARTICIPANTS\/MATERIALS, SETTING, METHODS<\/jats:title>\n                  <jats:p>Fertility outcomes (number of pregnancies, number of livebirths and age at first pregnancy) were compared between women with a male co-twin (exposed group, n\u2009=\u2009151) and those with a female co-twin (unexposed group, n\u2009=\u2009166). Population averaged models were used to estimate odds ratios (OR) and 95% CI for all outcomes with adjusting for potential confounders.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>MAIN RESULTS AND THE ROLE OF CHANCE<\/jats:title>\n                  <jats:p>There were no differences in chances of having pregnancies (adj. OR 1.33; 95% CI 0.72, 2.45) and livebirths (adj. OR 1.22; 95% CI 0.68, 2.18) between women from same-sex and opposite-sex twin pairs. Women with a male co-twin were more likely to smoke during pregnancy and, in the unadjusted model, were younger at their first pregnancy (OR 2.13; 95% CI 1.21, 3.75). After adjusting for confounding variables (year of birth and smoking status) the latter finding was no longer significant (OR 1.67; 95% CI 0.90, 3.20).<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>LIMITATIONS, REASONS FOR CAUTION<\/jats:title>\n                  <jats:p>The dataset was relatively small. For women without a pregnancy recorded in the databank, we assumed that they had not been pregnant.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>WIDER IMPLICATIONS OF THE FINDINGS<\/jats:title>\n                  <jats:p>Despite the evidence from animal studies concerning the adverse effects of prenatal testosterone exposure on female health, our results do not support the TTT hypothesis. The finding that women with a male co-twin are more likely to smoke during pregnancy highlights the importance of considering post-socialisation and social effects in twin studies.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>STUDY FUNDING\/COMPETING INTEREST(S)<\/jats:title>\n                  <jats:p>European Union\u2019s Horizon 2020 research and innovation programme under the Marie Sk\u0142odowska-Curie project PROTECTED (grant agreement No. 722634) and FREIA project (grant agreement No. 825100). No competing interests.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>TRIAL REGISTRATION NUMBER<\/jats:title>\n                  <jats:p>N\/A<\/jats:p>\n               <\/jats:sec>","DOI":"10.1093\/humrep\/deaa091","type":"journal-article","created":{"date-parts":[[2020,4,8]],"date-time":"2020-04-08T11:11:55Z","timestamp":1586344315000},"page":"1702-1711","source":"Crossref","is-referenced-by-count":3,"title":["Testing the twin testosterone transfer hypothesis\u2014intergenerational analysis of 317 dizygotic twins born in Aberdeen, Scotland"],"prefix":"10.1093","volume":"35","author":[{"given":"Chiara","family":"Talia","sequence":"first","affiliation":[{"name":"Institute of Medical Sciences, School of Medicine, Medical Sciences & Nutrition, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Edwin-Amalraj","family":"Raja","sequence":"additional","affiliation":[{"name":"Institute of Applied Health Sciences, University of Aberdeen, Aberdeen AB25 2ZD, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Sohinee","family":"Bhattacharya","sequence":"additional","affiliation":[{"name":"Institute of Applied Health Sciences, University of Aberdeen, Aberdeen AB25 2ZD, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Paul A","family":"Fowler","sequence":"additional","affiliation":[{"name":"Institute of Medical Sciences, School of Medicine, Medical Sciences & Nutrition, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"286","published-online":{"date-parts":[[2020,6,19]]},"reference":[{"key":"2020081807564379300_deaa091-B1","doi-asserted-by":"crossref","first-page":"115","DOI":"10.1016\/j.annepidem.2016.11.011","article-title":"Early-life mortality risks in opposite-sex and same-sex twins: a Danish cohort study of the twin testosterone transfer hypothesis","volume":"27","author":"Ahrenfeldt","year":"2017","journal-title":"Ann Epidemiol"},{"key":"2020081807564379300_deaa091-B2","doi-asserted-by":"crossref","first-page":"389","DOI":"10.1093\/ije\/dyv356","article-title":"Data resource profile: The Aberdeen Maternity and Neonatal Databank (AMND)","volume":"45","author":"Ayorinde","year":"2016","journal-title":"Int J Epidemiol"},{"key":"2020081807564379300_deaa091-B3","doi-asserted-by":"crossref","first-page":"61","DOI":"10.1186\/s13293-017-0134-x","article-title":"Does the sex of one\u2019s co-twin affect height and BMI in adulthood? A study of dizygotic adult twins from 31 cohorts","volume":"8","author":"Bogl","year":"2017","journal-title":"Biol Sex Differ"},{"key":"2020081807564379300_deaa091-B4","doi-asserted-by":"crossref","first-page":"6749","DOI":"10.1073\/pnas.1812786116","article-title":"Evidence that prenatal testosterone transfer from male twins reduces the fertility and socioeconomic success of their female co-twins","volume":"116","author":"B\u00fctikofer","year":"2019","journal-title":"Proc Natl Acad Sci USA"},{"key":"2020081807564379300_deaa091-B5","doi-asserted-by":"crossref","first-page":"230","DOI":"10.1016\/j.yhbeh.2004.10.006","article-title":"Is there an effect of prenatal testosterone on aggression and other behavioral traits? A study comparing same-sex and opposite-sex twin girls","volume":"47","author":"Cohen-Bendahan","year":"2005","journal-title":"Horm Behav"},{"key":"2020081807564379300_deaa091-B6","doi-asserted-by":"crossref","first-page":"373","DOI":"10.1093\/ije\/7.4.373","article-title":"Improper use of statistical significance testing in studying covariables","volume":"7","author":"Dales","year":"1978","journal-title":"Int J Epidemiol"},{"key":"2020081807564379300_deaa091-B7","doi-asserted-by":"crossref","first-page":"868","DOI":"10.1111\/acer.12035","article-title":"Investigating the influence of prenatal androgen exposure and sibling effects on alcohol use and alcohol use disorder in females from opposite-sex twin pairs","volume":"37","author":"Ellingson","year":"2013","journal-title":"Alcohol Clin Exp Res"},{"key":"2020081807564379300_deaa091-B8","doi-asserted-by":"crossref","first-page":"8","DOI":"10.1186\/s13229-016-0074-z","article-title":"Effect of co-twin gender on neurodevelopmental symptoms: A twin register study","volume":"7","author":"Eriksson","year":"2016","journal-title":"Mol Autism"},{"key":"2020081807564379300_deaa091-B9","author":"Harrel","year":"2001"},{"key":"2020081807564379300_deaa091-B10","doi-asserted-by":"crossref","first-page":"285","DOI":"10.1186\/s12884-018-1896-9","article-title":"Is there a relationship between fetal sex and placental pathological characteristics in twin gestations?","volume":"18","author":"Jahanfar","year":"2018","journal-title":"BMC Pregnancy Childbirth"},{"key":"2020081807564379300_deaa091-B11","doi-asserted-by":"crossref","first-page":"1023","DOI":"10.1007\/s00404-019-05088-x","article-title":"Association of twins\u2019 sex discordance and age at menarche","volume":"299","author":"Jahanfar","year":"2019","journal-title":"Arch Gynecol Obstet"},{"key":"2020081807564379300_deaa091-B12","doi-asserted-by":"crossref","first-page":"6300","DOI":"10.1038\/s41598-018-24634-2","article-title":"Birth size and gestational age in opposite-sex twins as compared to same-sex twins: An individual-based pooled analysis of 21 cohorts","volume":"8","author":"Jelenkovic","year":"2018","journal-title":"Sci Rep"},{"key":"2020081807564379300_deaa091-B13","doi-asserted-by":"crossref","first-page":"603","DOI":"10.1111\/j.1365-2605.2006.00701.x","article-title":"Early exposure to smoking and future fecundity among Danish twins","volume":"29","author":"Jensen","year":"2006","journal-title":"Int J Androl"},{"key":"2020081807564379300_deaa091-B14","doi-asserted-by":"crossref","first-page":"10","DOI":"10.1016\/j.placenta.2016.12.008","article-title":"Review: sexual dimorphism in the formation, function and adaptation of the placenta","volume":"54","author":"Kalisch-Smith","year":"2017","journal-title":"Placenta"},{"key":"2020081807564379300_deaa091-B15","first-page":"739","article-title":"Common genetic influences on BMI and age at menarche","volume":"67","author":"Kaprio","year":"1995","journal-title":"Hum Biol"},{"issue":"28","key":"2020081807564379300_deaa091-B16","article-title":"A comparison of anthropometric, metabolic, and reproductive characteristics of young adult women from opposite-sex and same-sex twin pairs","volume":"5","author":"Korsoff","year":"2014","journal-title":"Front Endocrinol"},{"key":"2020081807564379300_deaa091-B17","doi-asserted-by":"crossref","first-page":"1527","DOI":"10.1016\/j.fertnstert.2015.08.016","article-title":"Mid-pregnancy, perinatal, and neonatal reproductive endocrinology: a prospective cohort study in twins and singleton control subjects","volume":"104","author":"Kuijper","year":"2015","journal-title":"Fertil Steril"},{"key":"2020081807564379300_deaa091-B18","doi-asserted-by":"crossref","first-page":"1987","DOI":"10.1210\/jc.2009-0191","article-title":"Prevalence of polycystic ovary syndrome in women from opposite-sex twin pairs","volume":"94","author":"Kuijper","year":"2009","journal-title":"J Clin Endocrinol Metab"},{"key":"2020081807564379300_deaa091-B19","doi-asserted-by":"crossref","first-page":"33","DOI":"10.1016\/j.rbmo.2013.03.009","article-title":"Reproductive hormone concentrations in pregnancy and neonates: a systematic review","volume":"27","author":"Kuijper","year":"2013","journal-title":"Reprod Biomed Online"},{"key":"2020081807564379300_deaa091-B20","doi-asserted-by":"crossref","first-page":"21","DOI":"10.1023\/A:1021452630561","article-title":"A comparison of adult female twins from opposite-sex and same-sex pairs on variables related to reproduction","volume":"28","author":"Loehlin","year":"1998","journal-title":"Behav Genet"},{"key":"2020081807564379300_deaa091-B21","doi-asserted-by":"crossref","first-page":"19","DOI":"10.1023\/A:1002082325784","article-title":"Dimensions of psychological masculinity-femininity in adult twins from opposite-sex and same-sex pairs","volume":"30","author":"Loehlin","year":"2000","journal-title":"Behav Genet"},{"key":"2020081807564379300_deaa091-B22","doi-asserted-by":"crossref","first-page":"10915","DOI":"10.1073\/pnas.0605875104","article-title":"Male twins reduce fitness of female co-twins in humans","volume":"104","author":"Lummaa","year":"2007","journal-title":"Proc Natl Acad Sci USA"},{"key":"2020081807564379300_deaa091-B23","doi-asserted-by":"crossref","first-page":"481","DOI":"10.1375\/twin.11.5.481","article-title":"Males do not reduce the fitness of their female co-twins in contemporary samples","volume":"11","author":"Medland","year":"2008","journal-title":"Twin Res Hum Genet"},{"key":"2020081807564379300_deaa091-B24","doi-asserted-by":"crossref","first-page":"125","DOI":"10.1093\/oxfordjournals.aje.a115101","article-title":"The impact of confounder selection criteria on effect estimation","volume":"129","author":"Mickey","year":"1989","journal-title":"Am J Epidemiol"},{"key":"2020081807564379300_deaa091-B25","doi-asserted-by":"crossref","first-page":"397","DOI":"10.1007\/s11577-015-0319-4","article-title":"The biodemography of fertility: a review and future research frontiers","volume":"67(Suppl 1","author":"Mills","year":"2015","journal-title":"Kolner Z Soz Sozialpsychol"},{"key":"2020081807564379300_deaa091-B26","article-title":"Alternative (backdoor) androgen production and masculinization in the human fetus","volume":"17","author":"O'Shaughnessy","year":"2019","journal-title":"PLoS Biol"},{"key":"2020081807564379300_deaa091-B27","doi-asserted-by":"crossref","first-page":"629","DOI":"10.1111\/j.1728-4457.2015.00088.x","article-title":"Twinning rates in developed countries: trends and explanations","volume":"41","author":"Pison","year":"2015","journal-title":"Popul Dev Rev"},{"key":"2020081807564379300_deaa091-B28","doi-asserted-by":"crossref","first-page":"323","DOI":"10.1007\/BF01067432","article-title":"Sensation seeking in opposite-sex twins: an effect of prenatal hormones?","volume":"23","author":"Resnick","year":"1993","journal-title":"Behav Genet"},{"key":"2020081807564379300_deaa091-B29","doi-asserted-by":"crossref","first-page":"430","DOI":"10.1159\/000111240","article-title":"Effects of prenatal testosterone on sexual behavior, reproductive morphology and l h secretion in the female rat","volume":"19","author":"Rhees","year":"1997","journal-title":"Dev Neurosci"},{"key":"2020081807564379300_deaa091-B30","doi-asserted-by":"crossref","first-page":"263","DOI":"10.1111\/1467-9280.00448","article-title":"Femininity and fertility in sisters with twin brothers: prenatal androgenization? Cross-sex socialization?","volume":"13","author":"Rose","year":"2002","journal-title":"Psychol Sci"},{"key":"2020081807564379300_deaa091-B31","doi-asserted-by":"crossref","first-page":"665","DOI":"10.1016\/S0149-7634(02)00038-6","article-title":"Intrauterine position effects","volume":"26","author":"Ryan","year":"2002","journal-title":"Neurosci Biobehav Rev"},{"key":"2020081807564379300_deaa091-B32","doi-asserted-by":"crossref","first-page":"23","DOI":"10.1111\/j.1365-3016.2005.00576.x","article-title":"The twin placenta: framework for gross analysis in fetal origins of adult disease initiatives","volume":"19(Suppl. 1","author":"Salafia","year":"2005","journal-title":"Paediatr Perinat Epidemiol"},{"key":"2020081807564379300_deaa091-B33","doi-asserted-by":"crossref","first-page":"533","DOI":"10.1007\/s10519-010-9416-3","article-title":"Sensation seeking in females from opposite-versus same-sex twin pairs: hormone transfer or sibling imitation?","volume":"41","author":"Slutske","year":"2011","journal-title":"Behav Genet"},{"key":"2020081807564379300_deaa091-B34","doi-asserted-by":"crossref","first-page":"713","DOI":"10.1016\/j.yhbeh.2011.08.011","article-title":"Evaluating the twin testosterone transfer hypothesis: a review of the empirical evidence","volume":"60","author":"Tapp","year":"2011","journal-title":"Horm Behav"},{"key":"2020081807564379300_deaa091-B35","first-page":"2901","article-title":"Effects of maternal smoking on offspring reproductive outcomes: an intergenerational study in the North East of Scotland","volume":"25","author":"Tweed","year":"2017","journal-title":"Hum Reprod"},{"key":"2020081807564379300_deaa091-B36","doi-asserted-by":"crossref","first-page":"87","DOI":"10.1017\/thg.2016.8","article-title":"Individual differences in personality masculinity-femininity: examining the effects of genes, environment, and prenatal hormone transfer","volume":"19","author":"Verweij","year":"2016","journal-title":"Twin Res Hum Genet"},{"key":"2020081807564379300_deaa091-B37","doi-asserted-by":"crossref","first-page":"2901","DOI":"10.1093\/humrep\/deq235","article-title":"In utero exposure to tobacco smoke and subsequent reduced fertility in females","volume":"25","author":"Ye","year":"2010","journal-title":"Hum Reprod"}],"container-title":["Human Reproduction"],"original-title":[],"language":"en","link":[{"URL":"http:\/\/academic.oup.com\/humrep\/article-pdf\/35\/7\/1702\/33660433\/deaa091.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"http:\/\/academic.oup.com\/humrep\/article-pdf\/35\/7\/1702\/33660433\/deaa091.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2020,8,18]],"date-time":"2020-08-18T12:01:31Z","timestamp":1597752091000},"score":1,"resource":{"primary":{"URL":"https:\/\/academic.oup.com\/humrep\/article\/35\/7\/1702\/5859933"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2020,6,19]]},"references-count":37,"journal-issue":{"issue":"7","published-online":{"date-parts":[[2020,6,19]]},"published-print":{"date-parts":[[2020,7,1]]}},"URL":"https:\/\/doi.org\/10.1093\/humrep\/deaa091","relation":{},"ISSN":["0268-1161","1460-2350"],"issn-type":[{"value":"0268-1161","type":"print"},{"value":"1460-2350","type":"electronic"}],"subject":[],"published-other":{"date-parts":[[2020,7]]},"published":{"date-parts":[[2020,6,19]]}}}