title: Sex-typed play in opposite-sex twins.
abstract: To examine possible prenatal hormonal influences on sex-typed play, we compared girls with a boy co-twin to girls with a girl co-twin and girls with an older brother. In opposite-sex dizygotic twin pairs, the uterine environment may allow transfer of testosterone from the male to the female fetus. Singletons with an older brother provide a control for shared social environment. Girls aged 3 to 8 years (N = 91) were observed playing with sex-typed toys, and mothers completed questionnaires about the child's activities. Contrary to expectation, girls with a boy co-twin did not spend more time playing with boys' toys than girls with a girl co-twin or girls with an older brother. Although these results might suggest that normal variations in hormones do not contribute to within-sex variations in childhood activities, they combine with other work to suggest factors to consider in evaluating hormonal influences on human behavior, including level and timing of exposure.
authors.affiliation: Department of Psychology, Finch University of Health Sciences, Chicago Medical School, IL 60064, USA.
authors.forename: B A
authors.initials: BA
authors.lastname: Henderson
authors.forename: S A
authors.initials: SA
authors.lastname: Berenbaum
mesh_terms: D002648:Child; D002675:Child, Preschool; D005260:Female; D005783:Gender Identity; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D010552:Personality Assessment; D010988:Play and Playthings; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D012733:Sex Differentiation / Q000502:physiology*; D012931:Social Environment; D013240:Stereotyping; D013739:Testosterone / Q000502:physiology*; D014429:Twins, Dizygotic / Q000523:psychology*
chemical_list: D013739:Testosterone