title: Prenatal testosterone and stuttering.
abstract: BACKGROUND
  The prevalence of stuttering is much higher in males compared to females. The biological underpinnings of this skewed sex-ratio is poorly understood, but it has often been speculated that sex hormones could play an important role.
  
  
  OBJECTIVE
  The present study investigated a potential link between prenatal testosterone and stuttering. Here, an indirect indicator of prenatal testosterone levels, the Digit Ratio (2D:4D) of the hand, was used. As numerous studies have shown, hands with more "male" characteristics (putatively representing greater prenatal testosterone levels) are characterized by a longer ring finger compared to the index finger (represented as a lower 2D:4D ratio) in the general population.
  We searched for differences in the 2D:4D ratios between 38 persons who stutter and 36 persons who do not stutter. In a second step, we investigated potential links between the 2D:4D ratio and the multifaceted symptomatology of stuttering, as measured by the Overall Assessment of the Speaker's Experience of Stuttering (OASES), in a larger sample of 44 adults who stutter.
  
  
  RESULTS
  In the first step, no significant differences in the 2D:4D were observed between individuals who stutter and individuals who do not stutter. In the second step, 2D:4D correlated negatively with higher scores of the OASES (representing higher negative experiences due to stuttering), and this effect was more pronounced for female persons who stutter.
  
  
  CONCLUSIONS
  The findings indicate for the first time that prenatal testosterone may influence individual differences in psychosocial impact of this speech disorder.
authors.affiliation: Department of Psychology, University of Ulm, Ulm, Germany. Electronic address: christian.montag@uni-ulm.de.
authors.forename: Christian
authors.initials: C
authors.lastname: Montag
authors.affiliation: Department of Psychology, University of Bonn, Bonn, Germany.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Bleek
authors.affiliation: Department of Psychology, University of Bonn, Bonn, Germany.
authors.forename: Svenja
authors.initials: S
authors.lastname: Breuer
authors.affiliation: Department for the Treatment of Stuttering, LVR Clinic Bonn, Bonn, Germany.
authors.forename: Holger
authors.initials: H
authors.lastname: Prüss
authors.affiliation: Department for the Treatment of Stuttering, LVR Clinic Bonn, Bonn, Germany.
authors.forename: Kirsten
authors.initials: K
authors.lastname: Richardt
authors.affiliation: Alexandria, VA, USA.
authors.forename: Susanne
authors.initials: S
authors.lastname: Cook
authors.affiliation: Department of Communication Science & Disorders, University of Pittsburgh, PA, USA.
authors.forename: J Scott
authors.initials: JS
authors.lastname: Yaruss
authors.affiliation: Department of Psychology, University of Bonn, Bonn, Germany; Center for Economics & Neuroscience, University of Bonn, Bonn, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Reuter
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D005260:Female; D005385:Fingers / Q000033:anatomy & histology*; D006801:Humans; D008297:Male; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000097:blood*; D012737:Sex Factors; D013342:Stuttering / Q000097:blood / Q000209:etiology*; D013739:Testosterone / Q000097:blood*
chemical_list: D013739:Testosterone
keywords: 2D:4D ratio; Case control; OASES; Prenatal testosterone; Stuttering