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Birth Order and Ratio of Brothers to Sisters in Spanish Transsexuals

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Abstract

Three Western studies have shown that male-to-female (MF) homosexual transsexuals tend to be born later than their siblings and to come from sibships with more brothers than sisters. The objective of this study was to determine whether these variables would be replicated in 530 MF and female-to-male (FM) Spanish transsexuals according to sexual orientation. The results showed that MF homosexual transsexuals had significantly more older brothers than the non-homosexual MF group. Compared with the expected rates in the general population, birth order was significantly higher in both MF (Slater’s Index = 0.59; Fraternal Index = 0.61; Sororal Index = 0.58) and FM homosexual transsexuals (Slater’s Index = 0.65; Fraternal Index = 0.68; Sororal Index = 0.67), and sibling sex ratio was significantly higher than expected in homosexual MF (sex ratio = 0.55) but not in homosexual FM transsexuals. No significant differences were found in the non-homosexual subgroups. The replication of the later birth order and sibling sex-ratio effect in MF homosexual transsexuals corroborates previous findings in a variety of groups from different cultures and may suggest a common mechanism underlying the etiology of transsexualism.

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References

  • American Psychiatric Association. (1994). Diagnostic and statistical manual of mental disorders (4th ed.). Washington, DC: Author.

    Google Scholar 

  • Bailey, J. M., Willerman, L., & Parks, C. (1991). A test of the maternal stress theory of human male homosexuality. Archives of Sexual Behavior, 20, 277–293.

    Article  PubMed  Google Scholar 

  • Blanchard, R. (1989). The classification and labelling of nonhomosexual gender dysphorics. Archives of Sexual Behavior, 18, 315–334.

    Article  PubMed  Google Scholar 

  • Blanchard, R. (1997). Birth order and sibling sex ratio in homosexual versus heterosexual males and females. Annual Review of Sex Research, 8, 27–67.

    PubMed  Google Scholar 

  • Blanchard, R. (2008). Review and theory of handedness, birth order, and homosexuality in men. Laterality, 13, 51–70.

    PubMed  Google Scholar 

  • Blanchard, R., & Sheridan, P. M. (1992). Sibship size, sibling sex ratio, birth order, and parental age in homosexual and nonhomosexual gender dysphorics. Journal of Nervous and Mental Disease, 180, 40–47.

    Article  PubMed  Google Scholar 

  • Blanchard, R., Zucker, K. J., Bradley, S. J., & Hume, C. S. (1995). Birth order and sibling sex ratio in homosexual male adolescents and probably prehomosexual feminine boys. Developmental Psychology, 31, 22–30.

    Article  Google Scholar 

  • Blanchard, R., Zucker, K. J., Cohen-Kettenis, P. T., Gooren, L. J. G., & Bailey, J. M. (1996). Birth order and sibling sex ratio in two samples of Dutch gender-dysphoric homosexual males. Archives of Sexual Behavior, 25, 495–514.

    Article  PubMed  Google Scholar 

  • Bogaert, A. F. (2005). Gender role/identity and sibling sex ratio in homosexual men. Journal of Sex and Marital Therapy, 31, 217–227.

    Article  PubMed  Google Scholar 

  • Cano, G., Bergero, T., Esteva, I., Giraldo, F., Gómez, M., & Gorneman, I. (2004). La construcción de la identidad de género en pacientes transexuales [Gender identity construction in transsexual patients]. Revista de la Asociación Española de Neuropsiquiatría, 90, 2840–2848.

    Google Scholar 

  • Cohen-Kettenis, P. T., & Gooren, L. J. G. (1999). Transsexualism: A review of etiology, diagnosis and treatment. Journal of Psychosomatic Research, 46, 315–333.

    Article  PubMed  Google Scholar 

  • Dörner, G., Schenk, B., Schmiedel, B., & Ahrens, L. (1983). Stressful events in prenatal life of bi-and homosexual men. Experimental and Clinical Endocrinology, 81, 83–87.

    Article  PubMed  Google Scholar 

  • Ellis, L., & Cole-Harding, S. (2001). The effects of prenatal stress, and of prenatal alcohol and nicotine exposure, on human sexual orientation. Physiology & Behavior, 74, 213–226.

    Article  Google Scholar 

  • Esteva, I., Giraldo, F., Bergero, T., Cano, G., Crespillo, C., Ruíz, S., et al. (2001). Unidad de Trastornos de Identidad de Género de Andalucía: Evaluación diagnóstica, tratamiento hormonal y quirúrgico de los pacientes con Transexualidad [Gender Identity Disorder Unit in Andalusia: Diagnostic evaluation, hormonal, and surgical treatment in transsexual patients]. Cirugía Plástica Iberolatinamericana, 27, 259–324.

    Google Scholar 

  • Esteva, I., Gonzalo, M., Yahyaoui, R., Domínguez, M., Bergero, T., Giraldo, F., et al. (2006). Epidemiología de la transexualidad en Andalucía, atención especial al grupo de adolescents [Epidemiology of transsexualism in Andalusia: Special attention to the adolescent group]. Cuadernos de Medicina Psicosomática y Psiquiatría de Enlace, 78, 65–70.

    Google Scholar 

  • Gómez-Gil, E., & Esteva de Antonio, I. (2006). Ser transexual [Being transexual]. Barcelona: Editorial Glosa.

  • Gómez-Gil, E., Trilla, A., Salamero, M., Godás, T., & Valdés, M. (2009). Sociodemographic, clinical, and psychiatric characteristics of transsexuals from Spain. Archives of Sexual Behavior, 38, 378–392.

    Article  PubMed  Google Scholar 

  • Green, R. (2000). Birth order and ratio of brothers to sisters in transsexuals. Psychological Medicine, 30, 789–795.

    Article  PubMed  Google Scholar 

  • Hare, L., Bernard, P., Sánchez, F. J., Baird, P. N., Vilain, E., Kennedy, T., et al. (2008). Androgen receptor repeat length polymorphism associated with male-to-female transsexualism. Biological Psychiatry, 65, 93–96.

    Article  PubMed  Google Scholar 

  • Jones, M. B., & Blanchard, R. (1998). Birth order and male homosexuality: Extension of Slater’s index. Human Biology, 70, 775–787.

    PubMed  Google Scholar 

  • MacCulloch, M. J., & Waddington, J. L. (1981). Neuroendocrine mechanisms and the aetiology of male and female homosexuality. British Journal of Psychiatry, 139, 341–345.

    Article  PubMed  Google Scholar 

  • Meyer, W., Bockting, W., Cohen-Kettenis, P., Coleman, E., DiCeglie, D., Devor, H., et al. (2001). The Harry Benjamin Gender Dysphoria Association’s standards of care for gender identity disorders, sixth version. Journal of Psychology and Human Sexuality, 13, 1–30.

    Article  Google Scholar 

  • Poasa, K. H., Blanchard, R., & Zucker, K. J. (2004). Birth order in transgendered males from Polynesia: A quantitative study of Samoan fa’affine. Journal of Sex and Marital Therapy, 30, 13–23.

    Article  PubMed  Google Scholar 

  • Slater, E. (1962). Birth order and maternal age of homosexuals. Lancet, i, 69–71.

    Article  Google Scholar 

  • Tsoi, W. F., Kok, L. P., & Long, F. Y. (1977). Male transsexualism in Singapore: A description of 56 cases. British Journal of Psychiatry, 131, 405–409.

    Article  PubMed  Google Scholar 

  • VanderLaan, D. P., & Vasey, P. L. (2009). Male sexual orientation in independent Samoa: Evidence for fraternal order and maternal fecundity effects. Archives of Sexual Behavior. doi:10.1007/s10508-009-9576-5.

  • Vasey, P. L., & VanderLaan, D. P. (2007). Birth order and male androphilia in Samoan fa’afafine. Proceedings of the Royal Society of London Series B: Biological Sciences, 247, 1437–1442.

    Article  Google Scholar 

  • World Health Organization. (1993). International classification of diseases: Diagnostic criteria for research (10th ed.). Geneva: Author.

    Google Scholar 

  • Zucker, K. J., & Blanchard, R. (1994). Re-analysis of Bieber et al.’s 1962 data on sibling sex ratio and birth order in male homosexuals. Journal of Nervous and Mental Disease, 182, 528–530.

    Article  PubMed  Google Scholar 

  • Zucker, K. J., Blanchard, R., Kim, T. S., Pae, C. U., & Lee, C. (2007). Birth order and sibling sex ratio in homosexual transsexual South Korean men: Effects of the male-preference stopping rule. Psychiatry and Clinical Neurosciences, 61, 529–533.

    Article  PubMed  Google Scholar 

  • Zucker, K. J., Green, R., Coates, S., Zuger, B., Cohen-Kettenis, P. T., Zecca, G. M., et al. (1997). Sibling sex ratio of boys with gender identity disorder. Journal of Child Psychology and Psychiatry, 38, 543–551.

    Article  PubMed  Google Scholar 

  • Zucker, K. J., Green, R., Garofano, C., Bradley, S. J., Willians, K., Rebach, H. M., et al. (1994). Prenatal gender preference of mothers of feminine and masculine boys: Relation to sibling sex composition and birth order. Journal of Abnormal Child Psychology, 22, 1–13.

    Article  PubMed  Google Scholar 

  • Zucker, K. J., Lightbody, S., Pecore, K., Bradley, S. J., & Blanchard, R. (1998). Birth order in girls with gender identity disorder. European Child and Adolescent Psychiatry, 7, 30–35.

    Article  PubMed  Google Scholar 

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Acknowledgements

This research was supported by grants SEJ2007-65686/PSIC, PI-0254/2007 JA, and MIG 238/2009.

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Authors and Affiliations

  1. Unidad de Identidad de Género, Instituto Clínic de Neurociencias, Servicio de Psiquiatría, Hospital Clínic, Universidad de Barcelona, Barcelona, Spain

    Esther Gómez-Gil & Manel Salamero

  2. Unidad de Trastornos de Identidad de Género, Servicio de Endocrinología, Hospital Carlos Haya, Málaga, Spain

    Isabel Esteva & M. Cruz Almaraz

  3. Unidad de Trastornos de Identidad de Género, Servicio de Ginecología, Hospital Carlos Haya, Málaga, Spain

    Rocío Carrasco

  4. Departamento de Psicobiología, Universidad de A Coruña, A Coruña, Spain

    Eduardo Pasaro

  5. Departamento de Psicobiología, UNED, Madrid, Spain

    Antonio Guillamon

  6. Department of Psychiatry, Institute Clinic of Neurosciences, Hospital Clínic, University of Barcelona, Villarroel 170, 08036, Barcelona, Spain

    Esther Gómez-Gil

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  1. Esther Gómez-Gil
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  2. Isabel Esteva
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  3. Rocío Carrasco
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  4. M. Cruz Almaraz
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  5. Eduardo Pasaro
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  6. Manel Salamero
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  7. Antonio Guillamon
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Correspondence to Esther Gómez-Gil.

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Gómez-Gil, E., Esteva, I., Carrasco, R. et al. Birth Order and Ratio of Brothers to Sisters in Spanish Transsexuals. Arch Sex Behav 40, 505–510 (2011). https://doi.org/10.1007/s10508-010-9614-3

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  • DOI: https://doi.org/10.1007/s10508-010-9614-3

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