Archives of Sexual Behavior

, Volume 36, Issue 2, pp 135–137 | Cite as

Monozygotic Twins Concordant for Female-to-Male Transsexualism: A Case Report

  • Hans KnoblauchEmail author
  • Andreas Busjahn
  • Bernhard Wegener
Letter to the Editor

Transsexualism is a rare phenotype with an estimated frequency varying between 1 in 10,000 up to 1 in 100,000 in male-to-female transsexualism (MTF) and 1 in 30,000 up to 1 in 400,000 in female-to-male transsexualism (FTM) (Cohen-Kettenis & Gooren, 1999). Various explanations have been suggested ranging from biological to psychosocial factors (Coates, 1990; Cohen-Kettenis & Gooren, 1999; Zucker & Bradley, 1995). Emerging evidence supports brain morphological, physical, and genetic differences in transsexual persons (Bosinski et al., 1997; Henningson et al., 2005; Kruiver et al., 2000; van Goozen, Slabbekoorn, Gooren, Sanders, & Cohen-Kettenis, 2002; Zhou, Hofman, Gooren, & Swaab, 1995). Nevertheless, little data exist supporting any single hypothesis. A few monozygotic (MZ) FTM and MTF twin pairs, concordant or discordant for transsexualism, have been reported (Segal, 2006). However, only a single MZ concordant FTM twin pair has been published (Sadeghi & Fakhrai, 2000). We report the...


Twin Pair Transsexualism Gender Identity Disorder Twin Sister Sexual Identity Development 
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  1. Anchersen, P. (1956). Problems of transvestism. Acta Psychiatrica Neurologica Scandinavica, 106(suppl.), 249–256.Google Scholar
  2. Boomsma, D., Busjahn, A., & Peltonen, L. (2002). Classical twin studies and beyond. Nature Review Genetics, 3, 872–882.CrossRefGoogle Scholar
  3. Bosinski, H. A., Schroder, I., Peter, M., Arndt, R., Wille, R., & Sippell, W. G. (1997). Anthropometrical measurements and androgen levels in males, females, and hormonally untreated female-to-male transsexuals. Archives of Sexual Behavior, 26, 143–157.PubMedCrossRefGoogle Scholar
  4. Buhrich, N., Bailey, J. M., & Martin, N. G. (1991). Sexual orientation, sexual identity, and sex-dimorphic behaviors in male twins. Behavior Genetics, 21, 75–96.PubMedCrossRefGoogle Scholar
  5. Coates, S. (1990). Ontogenesis of boyhood gender identity disorder. Journal of the American Academy of Psychoanalysis, 18, 414–438.PubMedGoogle Scholar
  6. Cohen-Kettenis, P. T., & Gooren, L. J. (1999). Transsexualism: A review of etiology, diagnosis and treatment. Journal of Psychosomatic Research, 46, 315–333.PubMedCrossRefGoogle Scholar
  7. Coolidge, F. L., Thede, L. L., & Young, S. E. (2002). The heritability of gender identity disorder in a child and adolescent twin sample. Behavior Genetics, 32, 251–257.PubMedCrossRefGoogle Scholar
  8. Diamond, M., & Hawk, S. T. (2004, August). Concordance for gender identity disorder among monozygotic and dizygotic twin pairs. Paper presented at the meeting of the American Psychological Association, Honolulu, HI.Google Scholar
  9. Garden, G. M. F., & Rothery, D. J. (1992). A female monozygotic twin pair discordant for transsexualism: Some theoretical implications. British Journal of Psychiatry, 161, 852–854.PubMedCrossRefGoogle Scholar
  10. Green, R. (2000). Family cooccurrence of “gender dysphoria”: Ten sibling or parent-child pairs. Archives of Sexual Behavior, 29, 499–507.PubMedCrossRefGoogle Scholar
  11. Green, R., & Stoller, R. J. (1971). Two monozygotic (identical) twin pairs discordant for gender identity. Archives of Sexual Behavior, 1, 321–327.CrossRefGoogle Scholar
  12. Henningsson, S., Westberg, L., Nilsson, S., Lundström, B., Ekselius, L., Bodlund, O., et al. (2005). Sex steroid-related genes and male-to-female transsexualism. Psychoneuroendocrinology, 30, 657–664.PubMedCrossRefGoogle Scholar
  13. Hyde, C., & Kenna, J. C. (1977). A male MZ twin pair, concordant for transsexualism, discordant for schizophrenia. Acta Psychologica Scandinavica, 56, 265–275.Google Scholar
  14. McKee, E. A., Roback, H. B., & Hollander, M. H. (1976). Transsexualism in two male triplets. American Journal of Psychiatry, 133, 334–337.PubMedGoogle Scholar
  15. Kruijver, F. P., Zhou, J. N., Pool, C. W., Hofman, M. A., Gooren, L. J., & Swaab, D. F. (2000). Male-to-female transsexuals have female neuron numbers in a limbic nucleus. Journal of Clinical Endocrinology and Metabolism, 85, 2034–2041.PubMedCrossRefGoogle Scholar
  16. Sadeghi, M., & Fakhrai, A. (2000). Transsexualism in female monozygotic twins: A case report. Australian and New Zealand Journal of Psychiatry, 34, 862–864.PubMedCrossRefGoogle Scholar
  17. Segal, N. L. (2006). Two monozygotic twin pairs discordant for female-to-male transsexualism. Archives of Sexual Behavior, 35, 347–359.PubMedCrossRefGoogle Scholar
  18. van Goozen, S. H., Slabbekoorn, D., Gooren, L. J., Sanders, G., & Cohen-Kettenis, P. T. (2002). Organizing and activating effects of sex hormones in homosexual transsexuals. Behavior Neuroscience, 116, 982–988.CrossRefGoogle Scholar
  19. Zhou, J. N., Hofman, M. A., Gooren, L. J., & Swaab, D. F. (1995). A sex difference in the human brain and its relation to transsexuality. Nature, 378, 68–70.PubMedCrossRefGoogle Scholar
  20. Zucker, K. J., & Bradley, S. J. (1995). Gender identity disorder and psychosexual problems in children and adolescents. New York: Guilford Press.Google Scholar

Copyright information

© Springer Science+Business Media, LLC 2006

Authors and Affiliations

  • Hans Knoblauch
    • 1
    Email author
  • Andreas Busjahn
    • 2
  • Bernhard Wegener
    • 3
  1. 1.Vivantes Klinikum am UrbanKlinik für Psychiatrie und Psychotherapie, Dieffenbachstr. 1BerlinGermany
  2. 2.HealthTwist GmbHBerlin-BuchGermany
  3. 3.Vivantes Klinikum am UrbanKlinik für Psychiatrie und PsychotherapieBerlinGermany

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