title: Transsexualism in female monozygotic twins: a case report.
abstract: OBJECTIVE
  A case report is presented of a gender identity disorder involving a pair of female monozygotic twins who requested sex reassignment. As far as we know, this case is the first in psychiatric literature and supports a genetic aetiology of this disorder.
  
  
  METHODS
  The patients were two 18-year-old female monozygotic twins who had showed symptoms of transsexualism since early childhood. They had no other physical or psychiatric disorder except borderline mental functioning.
  
  
  METHODS
  The patients were referred for sex reassignment.
  
  
  RESULTS
  They were lost to follow up after initial evaluation.
  
  
  CONCLUSIONS
  In addition to other possible (yet not confirmed) causes of transsexualism, a genetic basis for this disorder is suggested by this case.
authors.affiliation: Roozbeh Psychiatric Hospital, Tehran University of Medical Sciences, Iran. sadeghimajid@yahoo.com
authors.forename: M
authors.initials: M
authors.lastname: Sadeghi
authors.forename: A
authors.initials: A
authors.lastname: Fakhrai
mesh_terms: D000293:Adolescent; D005260:Female; D005783:Gender Identity; D020022:Genetic Predisposition to Disease; D006801:Humans; D007360:Intelligence; D007621:Karyotyping; D010808:Physical Examination; D012017:Referral and Consultation; D014189:Transsexualism / Q000235:genetics* / Q000523:psychology; D014430:Twins, Monozygotic