The US has issued what is believed to be its first ever intersex birth certificate,

Sara Kelly Keenan, 55, was born with male genes, female genitalia and mixed internal reproductive organs.

But an “elaborate lie” between the New York orphanage where she was placed in as a baby, her doctors and her adopted parents meant the truth was hidden from her for forty years.

But after the city issued her with a new birth certificate, she is understood to be the first US citizen to be designated as “intersex” on the document, instead of male or female.

She told The Independent: “There is nothing about being intersex that needs to be hidden or to be ashamed of. I wanted to change it so that children in the future will have a different experience than I had.

“And part of that is bringing intersex out of the shameful shadows — speaking about it as just another way that humans are made.

“As an abandoned hermaphrodite baby, a lot of people made decisions for me, including my sex and my name without my consent or input.

"It was very empowering for me to return to the scene of the crime.”

Although it is difficult to accurately measure, since intersex conditions are not always accurately diagnosed, some experts estimate that as many as one in every 1,500 babies are born with genitals that cannot be classified as male or female.

Despite being lied to about her gender identity for most of her life Ms Keenan, who now lives in California said she “always knew I wasn’t a normal female”.

She had grown to over six feet tall by the time she was 13. From 16, knew she would not ever be able to have children and that she would need to take hormones for the rest of her life to prevent her bones from becoming brittle.

“I’ve always felt like I was intergender, even before I knew about it,” she said.

Ms Keenan says she always knew she wasn't a 'normal girl' (Sara Kelly Keenan)

Around seven years ago, just before her father died, she asked him about it.

“He told me that he had found out about it when I was a teenager," she said. "The decision was made not to give me all the information because they thought it would confuse me in life.

“They were doing what they thought was the right thing to do. And we know now that it’s not the right thing to do.

"It results in lifelong depression, suicides, the feeling of not belonging anywhere, ever."

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There are few studies of the mental health of intersex people, but one Australian survey has shown that almost two thirds thought about killing themselves and one in five had attempted to do so.

When Ms Keenan found out, she said "it made me feel angry, naive, like I was played for a fool."

She added: "It made me feel like the people with authority believed there was something wrong with me that needed to be hidden from the world, and me.

“I really wanted the intersex designation on my birth certificate to say: it’s okay to be intersex," Ms Keenan said. "It’s just another way people come."

And she hopes her birth certificate paves the way for New York City to acknowledge "non-binary" as a designation on official documents.

This will make it possible for trans people – not just those with mixed gender anatomies – to be recognised.

"Right now the city of New York is acknowledging this as a medical reality, not as a gender reality," she said. "And the next step will be to encourage them to broaden their definition".

She added the current medical definition is leaving many non-binary people in a "limbo of suffering".