A difference in hypothalamic structure between heterosexual and homosexual men

@article{Levay1991ADI,
  title={A difference in hypothalamic structure between heterosexual and homosexual men},
  author={Simon Levay},
  journal={Science},
  year={1991},
  volume={253},
  pages={1034 - 1037}
}
  • S. Levay
  • Published 30 August 1991
  • Psychology, Biology
  • Science
The anterior hypothalamus of the brain participates in the regulation of male-typical sexual behavior. [] Key Method The volumes of four cell groups in this region [interstitial nuclei of the anterior hypothalamus (INAH) 1, 2, 3, and 4] were measured in postmortem tissue from three subject groups: women, men who were presumed to be heterosexual, and homosexual men. No differences were found between the groups in the volumes of INAH 1, 2, or 4. As has been reported previously, INAH 3 was more than twice as…

Brain research, gender and sexual orientation.

This finding refutes Dörner's hypothesis that homosexual males have a "female" hypothalamus and indicates that, in addition to genetic factors, a multitude of environmental and psychosocial factors may have profound influence on the sexual differentiation of the brain.

The Interstitial Nuclei of the Human Anterior Hypothalamus: An Investigation of Variation with Sex, Sexual Orientation, and HIV Status

Although there was a trend for INAH3 to occupy a smaller volume in homosexual men than in heterosexual men, there was no difference in the number of neurons within the nucleus based on sexual orientation.

" " Differential Brain Activation in Exclusively Homosexual and Heterosexual Men Produced by an SSRI

In the hypothalamus, the homosexual group exhibited a significantly smaller reduction in glucose metabolism in response to fluoxetine than the heterosexual group, which might be reflective of underlying neurochemical differences between homosexual and heterosexual men.

Sexual orientation and its basis in brain structure and function

  • D. Swaab
  • Psychology, Biology
    Proceedings of the National Academy of Sciences
  • 2008
It is reported that hemispheric ratios, as well as patterns of amygdala connectivity, were sex-atypical in homosexual individuals, with HoM exhibiting more female patterns than HeM and HoW showing more male-like features than HeW.

Male-to-female transsexuals have female neuron numbers in a limbic nucleus.

The present findings of somatostatin neuronal sex differences in the BSTc and its sex reversal in the transsexual brain clearly support the paradigm that in transsexuals sexual differentiation of the brain and genitals may go into opposite directions and point to a neurobiological basis of gender identity disorder.

A brain sexual dimorphism controlled by adult circulating androgens.

It is demonstrated that adult hormone manipulations can completely reverse a sexual dimorphism in brain regional volume in a mammalian species.

Sexual differentiation of the human hypothalamus.

The mechanisms causing sexual differentiation of hypothalamic nuclei, the pre- and postnatal factors influencing this process, and the exact functional consequences of the morphological and functional hypothalamic differences await further elucidation.

A sex difference in the hypothalamic uncinate nucleus: relationship to gender identity.

It is proposed that the sex reversal of the INAH3 in transsexual people is at least partly a marker of an early atypical sexual differentiation of the brain and that the changes in INah3 and the BSTc may belong to a complex network that may structurally and functionally be related to gender identity.
...

References

SHOWING 1-10 OF 43 REFERENCES

A neuroendocrine predisposition for homosexuality in men

Plasma testosterone levels and 24-hr urinary excretions of unconjugated testosterone of adult homosexual men were found to be in the normal range as observed in heterosexual men, suggesting that homosexual men possess a predominantly female-differentiated brain which may be activated to homosexual behavior by normal or approximately normal androgen levels in adulthood.

Two sexually dimorphic cell groups in the human brain

A quantitative analysis of the volume of 4 cell groups in the preoptic- anterior hypothalamic area (PO-AHA) and of the supraoptic nucleus (SON) of the human brain was performed in 22 age-matched male

A sexually dimorphic nucleus in the human brain.

A sexually dimorphic cell group is described in the preoptic area of the human hypothalamus, located within an area that is essential for gonadotropin release and sexual behavior in other mammals.

Homosexuality and genetic sex.

  • M. Pritchard
  • Psychology, Biology
    The Journal of mental science
  • 1962
It is concluded that Lang's hypothesis that some male homosexuals are genetically female can no longer be regarded as tenable and the nuclear sex of homosexuals has always proved to be consistent with the phenotypic sex.