Brain structure changes associated with sexual orientation

Scientific Reports, vol. 11, pp. 5078

Abstract

Biological sex differences in brain function and structure are reliably associated with several cortico-subcortical brain regions. While sexual orientation (hetero- versus homosexuality) has been similarly linked to functional differences in several phylogenetically-old brain areas, the research on morphological brain phenotypes associated with sexual orientation is far from conclusive. We examined potential cerebral structural differences linked to sexual orientation in a group of 74 participants, including 37 men (21 homosexual) and 37 women (19 homosexual) using voxel-based morphometry (VBM). Gray matter volumes (GMV) were compared with respect to sexual orientation and biological sex across the entire sample using full factorial designs controlling for total intracranial volume, age, handedness, and education. We observed a significant effect of sexual orientation for the thalamus and precentral gyrus, with more GMV in heterosexual versus homosexual individuals, and for the putamen, with more GMV in homosexual + than heterosexual individuals. We found significant interactions between biological sex and sexual orientation, indicating that the significant effect for the putamen cluster was driven by homosexual women, whereas heterosexual women had increased precentral gyrus GMV. Heterosexual men exhibited more GMV in the thalamus than homosexual men. This study shows that sexual orientation is reflected in brain structure characteristics and that these differ between the sexes. The results emphasize the need to include or control for potential effects of participants' sexual orientation in neuroimaging studies. Furthermore, our findings provide important new insights into the brain morphology underlying sexual orientation and likely have important implications for understanding brain functions and behavior.

Authors 7

1. Mikhail Votinov Aachen Department of Psychiatry, Psychotherapy and Psychosomatics Medical Faculty

   Forschungszentrum Jülich · RWTH Aachen University

   Affiliation as printed

   Department of Psychiatry, Psychotherapy and Psychosomatics, Medical Faculty, RWTH Aachen University, Aachen, Germany. mvotinov@ukaachen.de

   Institute of Neuroscience and Medicine 10, Research Centre Jülich, Jülich, Germany. mvotinov@ukaachen.de

   Institute of Neuroscience and Medicine 10, Research Centre Jülich, Jülich, Germany

2. Katharina S. Goerlich

   University Medical Center Groningen · University of Groningen

   Affiliation as printed

   Department of Biomedical Sciences of Cells and Systems, Section Cognitive Neuroscience, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands

3. Andrei Alexandru Puiu Aachen Department of Psychiatry, Psychotherapy and Psychosomatics Medical Faculty

   RWTH Aachen University

   Affiliation as printed

   Department of Psychiatry, Psychotherapy and Psychosomatics, Medical Faculty, RWTH Aachen University, Aachen, Germany

4. Elke Stefanie Smith

   University of Cologne

   Affiliation as printed

   Department of Psychology, Biological Psychology, University of Cologne, Cologne, Germany

5. Thomas K. Nickl-Jockschat

   University of Iowa

   Affiliation as printed

   Department of Neuroscience and Pharmacology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA

   Department of Psychiatry, Iowa Neuroscience Institute, University of Iowa, Carver College of Medicine, Iowa City, IA, USA

6. Birgit Derntl

   University of Tübingen

   Affiliation as printed

   Department of Psychiatry and Psychotherapy, Medical School, University of Tübingen, Tübingen, Germany

7. Ute Habel Aachen Department of Psychiatry, Psychotherapy and Psychosomatics Medical Faculty

   Forschungszentrum Jülich · RWTH Aachen University

   Affiliation as printed

   Department of Psychiatry, Psychotherapy and Psychosomatics, Medical Faculty, RWTH Aachen University, Aachen, Germany

   Institute of Neuroscience and Medicine 10, Research Centre Jülich, Jülich, Germany