A new study suggests that 1 in 5 non-binary people in the U.S. are denied healthcare due to their gender identity.

The study, published in the New England Journal of Medicine in December, described a need for medical professionals to improve the care of non-binarypatients.

“As our society’s concept of gender evolves, so does the visibility of contemporary nonbinary people,” said researchers at the start of the paper.

“Yet many members of the medical community may not know how to interact with nonbinary patients respectfully or recognize their unique needs and barriers to care.”

The paper, Persons of Nonbinary Gender — Awareness, Visibility, and Health Disparities, states that 19 percent of non-binary patients were refused medical treatment because of their gender identity. In the past year, 22 percent of these individuals avoided medical care due to fears of discrimination.

“Our findings really highlight that there’s a lot of scepticism and hesitancy around nonbinary and gender nonconforming patients to engage with healthcare professionals,” said Walter Liszewski, MD, University of Minnesota Medical School Dermatology Resident and author of the article.

The research also identified how non-binary individuals were more likely to have higher rates of psychological stress, higher rates of domestic abuse, higher rates of poverty and higher rates of unemployment compared to patients who don’t identify as non-binary.

Liszewski suggested that the health disparities could be associated with the levels of discrimination faced by non-binary patients by medical professionals.

“The medical literature in the medical communities is not keeping up to date with society,” Liszewski said.

“My hope is that physicians who read the article will become aware of nonbinary patients, and realize we need to do a better job of allowing these individuals to access quality healthcare.”

The study is released after legislation came into effect in New York City allowing residents to select a third gender on their birth certificates. California also recently adopted a self-ID gender recognition law allowing transgender and non-binary people in the state to update the gender listed on their state ID cards and driver’s licences.

Many medical forms still only provide male or female gender options, which can not only cause distress to non-binary patients but can also result in medical professionals misgendering them.

Despite this progress, the Trump administration announced in October it was considering re-defining gender as a “biological, immutable condition determined by genitalia at birth,” which led to protests from activists.