Brody's Notes... Researchers Discover Transsexual Differences Caught By Brain Scans

Sample MRI Scan

By Brody Levesque (Washington DC) JAN 25 | Researcher's at the National University of Distance Education in Madrid, Spain have discovered a technique that they say will assist doctors to identify transgender people at an early age, giving them more options for treatment, such as delaying the onset of puberty. The Spanish university's research team was led by Antonio Guillamon, MD, a professor of psychobiology in the university's Department of Psychobiology-School of Psychology. 

A 2010 study published by  Graduate Journal of Social Science in the UK, had found that of 121 transgender people surveyed, 38 per cent realised they had gender variance by age 5.  White matter differences could provide independent confirmation that such children might benefit from treatment to delay puberty.

This new National University of Distance Education study looked at the white matter of the brain and its structural differences in men, women and female-to-male transgender people by running MRI scans on the brains of 18 female-to-male transsexual people who'd had no treatment and compared them with those of 24 males and 19 females.

The study found significant differences between male and female brains in four regions of white matter – and the female-to-male transsexual people had white matter in these regions that resembled a male brain.

"It's the first time it has been shown that the brains of female-to-male transsexual people are masculinised," Guillamon says.

In another study, the team used the same technique to compare white matter in 18 male-to-female transsexual people with that in 19 males and 19 females. Surprisingly, in each transsexual person's brain the structure of the white matter in the four regions was halfway between that of the males and females.

"Their brains are not completely masculinised and not completely feminised, but they still feel female," says Guillamon.

A separate study at King's College in London, UK, suggests it may soon be possible to look for these differences in such children. Researchers there adapted an MRI scanner to be as quiet as possible so it could be used to monitor the development of white matter in sleeping infants. Using new image analysis software they could track when and where myelin – the neuron covering that makes white matter white – was laid down. Although the sample was too small to identify any gender differences in development, the scientists expect to see differences developing in the brain "by 2 or 3 years of age."