Transgender children may start to identify with toys and clothes typical of their gender identity from a very young age, a recent study suggests.

And their confidence in their gender identity is generally as strong as that of cisgender children, whose identity matches their sex assigned at birth, researchers found.

“Trans kids are showing strong identities and preferences that are different from their assigned sex,” lead author Selin Gulgoz said in a press statement. “There is almost no difference between these trans- and cisgender kids of the same gender identity — both in how, and the extent to which, they identify with their gender or express that gender.”

For the study, researchers interviewed 317 transgender children, ages 3 to 12, and 189 of the children’s siblings. They also interview 316 cisgender kids.

Researchers asked the children how much they felt like a boy or girl or something else. They also asked about preferences for toys and clothes that are stereotypically associated with one gender.

The transgender kids showed strong preferences for toys and clothing typically associated with their gender identity, not their assigned sex, the study found. Their preferences didn’t appear to differ based on how long they had lived as their current gender.

Transgender kids also didn’t appear to have preferences much different from cisgender children with the same gender identity, according to the report in the Proceedings of the National Academy of Sciences.

The similarities among transgender and cisgender children were surprising, researchers said, because early in life, the transgender kids had been treated as a gender other than the one they currently identify as.

“These findings suggest that children might not be simply learning about gender based on what their parents tell them about their own gender or how they treat them early on (which would be about the gender associated with their assigned sex),” Gulgoz told Reuters Health by email.

“Instead, the findings suggest that children may be selectively attending to broader social messages regarding the gender they feel they are, from early ages,” said Gulgoz did the work at the University of Washington in Seattle and will start a new position this winter at Fordham University.

Researchers traveled across the U.S. and Canada to meet transgender children and their parents at home or in their communities. They met each family for about an hour.

Children in the cisgender control group and their families lived in the Seattle area and answered all of the same questions as the families of transgender kids.

One limitation of the study is that all the transgender kids lived in families that affirmed their current gender identity, the study team notes. Their experiences might not reflect what would happen for transgender youth who lived in less supportive environments.

Researchers also only looked at children at one point in time. Gender expression or identity for some of them might shift in the future, or their level of support and affirmation might change.

In previous studies of cisgender children, it was always difficult to tease apart whether patterns were due to gender identity, sex assigned at birth or socialization experiences, said Dr. Stuart Chipkin of the University of Massachusetts Amherst, who wasn’t involved in the study.

The current study, Chipkin said by email, “helps to confirm the unique and separate reality of gender and how it is distinct from biological sex and socialization,” Chipkin added. “It supports the idea that gender is inherent and separate from biological sex which would seem to then come down on the side of nature as opposed to nurture.”

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