title: Age of onset and sexual orientation in transsexual males and females.
abstract: BACKGROUND
  With regard to transsexual developments, onset age (OA) appears to be the starting point of different psychosexual pathways.
  
  
  OBJECTIVE
  To explore differences between transsexual adults with an early vs. late OA.
  
  
  METHODS
  Data were collected within the European Network for the Investigation of Gender Incongruence using the Dutch Biographic Questionnaire on Transsexualism (Biografische Vragenlijst voor Transseksuelen) and a self-constructed score sheet according to the DSM-IV-TR (Diagnostic and Statistical Manual, Fourth Edition, Text Revision) criteria of Gender Identity Disorder (GID) and Gender Identity Disorder in Childhood (GIDC). One hundred seventy participants were included in the analyses.
  
  
  METHODS
  Transsexual adults who, in addition to their GID diagnosis, also fulfilled criteria A and B of GIDC ("a strong cross-gender identification,""persistent discomfort about her or his assigned sex") retrospectively were considered as having an early onset (EO). Those who fulfilled neither criteria A nor B of GIDC were considered as having a late onset (LO). Participants who only fulfilled criterion A or B of GIDC were considered a residual (RES) group.
  
  
  RESULTS
  The majority of female to males (FtMs) appeared to have an early OA (EO = 60 [77.9%] compared to LO = 10 [13%] and to RES = 7 [9.1%]). Within male to females (MtFs), percentages of EO and LO developments were more similar (EO = 36 [38.7%], LO = 45 [48.4%], RES = 12 [12.9%]). FtMs presented to gender clinics at an earlier age than MtFs (28.04 to 36.75). The number of EO vs. LO transsexual adults differed from country to country (Belgium, Germany, the Netherlands, Norway).
  
  
  CONCLUSIONS
  OA has a discriminative value for transsexual developments and it would appear that retrospective diagnosis of GIDC criteria is a valid method of assessment. Differences in OA and sex ratio exist between European countries.
authors.affiliation: Department of Sex Research and Forensic Psychiatry, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Timo O
authors.initials: TO
authors.lastname: Nieder
authors.forename: Melanie
authors.initials: M
authors.lastname: Herff
authors.forename: Susanne
authors.initials: S
authors.lastname: Cerwenka
authors.forename: Wilhelm F
authors.initials: WF
authors.lastname: Preuss
authors.forename: Peggy T
authors.initials: PT
authors.lastname: Cohen-Kettenis
authors.forename: Griet
authors.initials: G
authors.lastname: De Cuypere
authors.forename: Ira R Hebold
authors.initials: IR
authors.lastname: Haraldsen
authors.forename: Hertha
authors.initials: H
authors.lastname: Richter-Appelt
mesh_terms: D000328:Adult; D017668:Age of Onset; D001530:Belgium / Q000453:epidemiology; D016009:Chi-Square Distribution; D003430:Cross-Sectional Studies; D005260:Female; D005783:Gender Identity; D005858:Germany / Q000453:epidemiology; D006801:Humans; D008297:Male; D017533:Marital Status; D009426:Netherlands / Q000453:epidemiology; D009664:Norway / Q000453:epidemiology; D012737:Sex Factors; D012725:Sexual Behavior / Q000523:psychology*; D011795:Surveys and Questionnaires; D014189:Transsexualism / Q000453:epidemiology / Q000523:psychology*