Natalia Grace's adoptive parents accused her of being an adult. She says a DNA test confirmed her real age — here's what the results actually mean.

• "The Curious Case of Natalia Grace: Natalia Speaks" appears to make a definitive judgment about Natalia's age.
• A TruDiagnostic DNA blood test shows that her biological age is close to 22.

Natalia Grace's true age is much lower than her legal one — at least, according to the results of a DNA test she took while filming Max documentary "The Curious Case of Natalia Grace: Natalia Speaks."

In 2010, Michael and Kristine Barnett adopted Natalia, who they were told was a 6-year-old Ukrainian orphan. However, they came to believe that she was, in fact, an adult con artist, not unlike the 2009 horror movie "Orphan." The couple successfully petitioned a court to change her birth year from 2003 to 1989.

In 2013, following the successful petition, the Barnetts left Natalia, who has a rare form of dwarfism known as spondyloepiphyseal dysplasia, alone in an Indiana apartment and moved to Canada. While she was legally an adult, her disability status meant that she was still classified as a dependent, and the then-divorced couple faced neglect charges in 2019. Michael was acquitted in October 2022, and charges against Kristine were dismissed in March 2023.

In "Natalia Speaks," the second season of the documentary series currently available to stream on Max, Natalia Grace tells her side of the story. She disputes the Barnetts' claim that she was an adult masquerading as a child — and receives the results of a DNA test on-screen that appear to prove she's telling the truth.

Natalia Grace took a DNA test to find out her age in 'Natalia Speaks'

In season two, episode one of "The Curious Case of Natalia Grace," Natalia and her most recent adoptive father, Antwon Mans, consult the genetics testing company TruDiagnostic to help determine Natalia's biological age.

Dr. Halland Chen, an age specialist at TruDiagnostic, says in an interview in the series that by using a blood sample and examining their DNA, the company can determine someone's biological age. According to the National Institute on Aging, biological age is the "true age that our cells, tissues, and organ systems appear to be, based on biochemistry." However, as Business Insider previously reported, biological age is not a straightforward way of measuring how old a person is. Some medical professionals do not embrace biological age as a measurement because, they say, there isn't a standard way for cells to age.

TruDiagnostic's assessment indicated that Natalia's biological age was close to 22. At the time, Natalia suspected she was about 20 years old. Her legal age, however, would have been close to 33, given that the Barnetts changed her legal birth year from 2003 to 1989.

"This one little piece of paper throws every single lie that the Barnetts have said right into the trash with a match," Natalia says after receiving the results.

Testimony from another medical professional in the documentary also appeared to validate Natalia's claim of her age. Natalia's childhood dentist, Dr. Timothy Gossweiler, said that when he saw Natalia in 2011, Kristine Barnett asked him to estimate Natalia's age based on her teeth.

Gossweiler displays Natalia's 2011 x-ray, highlighting that she still had 12 remaining baby teeth at the time. According to Gossweiler, that would have placed Natalia's age at the time somewhere between six and nine years old.

"This is way too many baby teeth to be an adult," Gossweiler said. "It's indisputable. You can't fake teeth coming in like this."

In an email to Business Insider, Katherine Barnett said she and her then-husband "did not incite the reaging of Natalia, the local police department detective, Detective Clouse did." She also said that "Natalia was found by many parties, forensic evidence, and state law enforcement outside of myself and Michael to be an adult."

DNA tests like the one Natalia Grace took are more of a health measurement than a method of determining how old you are

Natalia Grace used TruDiagnostic testing in an attempt to calculate her true age. But these tests are more commonly used as a kind of health measurement.

Chronological age is how old you are according to your birth date. Biological age is ostensibly a measure of how fast you're aging according to your cells, tissues, and organ systems.

In theory, the older your biological age, the more likely you are to develop age-related diseases such as cancer or dementia.

Research shows your cells can age prematurely. Depression, lack of sleep, stress, violence, and poverty are all linked to accelerated cell aging, according to a systematic review.

Some longevity researchers believe there are ways to "reverse" our biological age. For example, Steve Horvath, who invented a way to measure biological age, says he reversed his biological age by 4 years by eating less sugar and more vegetables, quitting smoking, and exercising more. Harvard biologist David Sinclair previously told Business Insider in March 2023 that while his chronological age at the time was 54, his biological age was 44. Sinclair believes his carefully crafted lifestyle keeps his cells young.

So while Natalia's DNA results — and her former dentist's testimony — do suggest that she was actually a child at the time the Barnetts left her in Indiana, it's not quite a way to pinpoint her precise chronological age based on her date of birth.