title: Mental rotation in female fraternal twins: Evidence for intra-uterine hormone transfer?
abstract: Men outperform women in mental rotation by about one standard deviation. Prenatal exposure to testosterone has been suggested as one cause. In animals it has been shown that a female fetus located between two male ones is exposed to higher levels of testosterone. It is still unclear whether intra-uterine hormone transfer exists in humans. Therefore, the influence of an intra-uterine presence of a male co twin was studied in female fraternal twins (N=200). Women with a male co-twin outperformed women with a female co-twin by about a third standard deviation. In a no-twin control group (N=200), performance of women with a slightly older sibling did not depend upon the sibling's sex. These findings provide preliminary support for the theory of an influence of prenatal testosterone on mental rotation performance.
authors.affiliation: Heinrich-Heine University, Düsseldorf, Germany. Martin.Heil@uni-duesseldorf.de
authors.forename: Martin
authors.initials: M
authors.lastname: Heil
authors.forename: Michael
authors.initials: M
authors.lastname: Kavšek
authors.forename: Bettina
authors.initials: B
authors.lastname: Rolke
authors.forename: Christian
authors.initials: C
authors.lastname: Beste
authors.forename: Petra
authors.initials: P
authors.lastname: Jansen
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D005260:Female; D006801:Humans; D008606:Mental Processes / Q000502:physiology*; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D013739:Testosterone / Q000009:adverse effects*; D014163:Transfer, Psychology; D014429:Twins, Dizygotic; D014430:Twins, Monozygotic; D055815:Young Adult
chemical_list: D013739:Testosterone