Two landmark reports are establishing a link between genetics and being trans.

In a new study published in Scientific Reports, researchers at the University of São Paulo compared the brains of cisgender and transgender people. Using MRI scans, they found that the volume of the insula cortex—a region of the brain associated with self-awareness, cognitive functioning, and empathy—differed greatly between the two groups.

The paper theorized that "these alterations in the insula could be related to the neural network of body perception and reflect the distress that accompanies gender dysphoria." Lead author Giancarlo Spizzirri says the findings lend credibility to a "born this way" sort of argument.

"We found that trans people have characteristics that bring them closer to the gender with which they identify and their brains have particularities, suggesting that the differences begin to occur during gestation," he wrote in a statement. "The evidence is building that it’s not a matter of ideology."

Meanwhile, another study out of Augusta University uncovered rare genetic variations among transgender people. Researchers sequenced the DNA of 14 trans men and 16 trans woman and, for the first time, were able to pinpoint a panel of genes shared by the subjects that could explain feelings of gender dysphoria. They found 30 rare genetic variants shared by participants—nine of which were involved in the growth of brain cells or the production of sex hormones.

The research is still in progress, but it lines up with earlier studies.

"There is a growing amount of scientific evidence that... there is a biological basis for these unusual gender identities, just as there is for being right or left-handed," Bernard Reed, founder of the U.K.'s Gender Identity Research and Education Society, told Gay Times. Already, this has led to acceptance within the World Health Organisation and NHS England that the development of an unusual gender identity is not a mental illness.”