In some research papers, transsexuality is correlated with measurable differences in brain structure. For example:
- Zhou et al. (1995) inspected the central subdivision of the bed nucleus of the stria terminalis (BSTc), and found female-sized BSTc's in male-to-female transsexuals.
- Berglund et al. (2008) found female-like hypothalamus activation in male-to-female transsexuals in response to smelling odorous steroids.
If there is a neurobiological basis for transsexuality, it seems reasonable to expect to see transsexuality in non-human animals. This leads me to my question:
Has transsexuality been observed in animals other than humans, and how was it observed?
- Zhou et al., A sex difference in the human brain and its relation to transsexuality, Nature 378 (1995), 68-70.
- Berglund et al., Male-to-Female Transsexuals Show Sex-Atypical Hypothalamus Activation When Smelling Odorous Steroids, Cereb. Cortex 18 (2008), 1900-1908.