A new Australian study has uncovered evidence of a genetic link underpinning gender dysphoria in transgender people.
The research, published in the Journal of Clinical Endocrinology and Metabolism, suggests a link between being transgender and changes in genes that process the sex hormones estrogen and androgen.
For the study, scientists at Melbourne’s Hudson Institute of Medical Research analysed DNA from 380 transgender women and the findings were compared to the DNA of 344 cisgender men.
Researchers used the data to examine 12 genes which determine hormone signalling and found four of them had small but significant differences in trans women compared to men.
The study suggests these genetic changes may alter the levels of sex hormones that determine gender identity in a brain that’s developing.
“We know sex hormones like androgens and estrogens have really powerful effects on behaviour… But we don’t know if they have effects on gender identity. This points to a role,” the study’s senior author Professor Vincent Harley told Fairfax Media.
“We have found a few weak contributors. And there are likely to be very many other genes involved.”
Professor Harley said it “should not hinge on science to validate people’s individuality and lived experience” of gender, but the research may help reduce discrimination, improve diagnosis or treatment of gender dysphoria, and reduce the distress experienced by trans people.
“People with gender dysphoria have increased rates of depression, anxiety, eating disorders, self-harm and suicide,” he said.
Medical acceptance of trans people
One study participant, Fran, told Fairfax she signed up for the study because it might help address medical discrimination towards trans people.
“I agreed to be in this study because I thought it might help people,” she said.
“That greater medical acceptance, potentially it saves lives.
“If this serves to open people’s minds a little bit, and create some way for people to accept the diversity that is there already, then it’s a good thing.”
Transgender Victoria spokesperson Sally Goldner warned such research must not be used to undermine people’s sense of identity.
“It’s helpful to have evidence that says trans people are who we are – as we always knew,” she said.
“But a genetic study should never invalidate someone’s sense of identity.”
A number of previous studies have also suggested a genetic basis for gender dysphoria in trans people.
A South American study published in March compared MRI scans of the brains of cisgender and transgender people, and found that the volume of the brain’s insular cortex — associated with self-awareness and cognitive functioning — differed between the two groups.
That study’s researchers found trans people “have characteristics that bring them closer to the gender with which they identify and their brains have particularities” that may start in the womb.
A separate study earlier this year by US researchers sequenced the DNA of 14 trans men and 16 trans woman and discovered a panel of rare genes shared by the subjects that may explain their gender dysphoria.