Masculinized Finger-Length Ratios of Boys, but Not Girls, Are Associated With Attention-Deficit/Hyperactivity Disorder

Michelle M. Martel, Kyle L. Gobrogge, S. Marc Breedlove, Joel T. Nigg

Research output: Contribution to journalArticlepeer-review

67 Scopus citations


Gonadal hormones may exert permanent organizational effects on sexually dimorphic finger-length ratios and sexually dimorphic behavior expressed in childhood attention deficit-hyperactivity disorder (ADHD). This study extended recent work examining associations between finger-length ratios (specifically, 2D:4D) and ADHD in a well-characterized, clinically diagnosed, community-recruited sample of boys and girls. A multistage, diagnostic procedure was utilized to identify 113 children with ADHD and 137 non-ADHD comparison children. Right-hand digit ratios showed significant mean differences by gender, as well as associations with ADHD diagnosis. Boys with ADHD had more masculinized digit ratios than control-group boys. More masculine right 2D:4D and 3D:4D ratios were correlated with parent- and teacher-rated inattentive and hyperactive-impulsive symptoms in boys but not in girls. Masculinized finger-length ratios were associated with hyperactive-impulsive and oppositional-defiant symptoms, but associations were largest with symptoms of inattention. It is concluded that prenatal, organizational effects of gonadal hormones may play a role in the development of ADHD and contribute to explaining sex differences in the prevalence rates of this childhood disorder.

Original languageEnglish
Pages (from-to)273-281
Number of pages9
JournalBehavioral Neuroscience
Issue number2
StatePublished - Apr 2008


  • 2D:4D
  • ADHD
  • finger-length ratio
  • sex differences
  • testosterone

ASJC Scopus subject areas

  • Behavioral Neuroscience


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