Taylor's 'birthmark' turned out to be a symptom of something she thought was impossible.

Taylor Muhl is her own twin.

Yep, really.

Muhl, a singer/songwriter, only found out she had a rare condition called chimerism a few years ago. Muhl absorbed her own twin in the womb and now she has two immune systems – her own and her twin sister’s.

Growing up Muhl always felt like she was different. She had a line down the center of her stomach, and on one side of the line the skin colour was notably darker than the skin on the rest of her body.

The doctors put it down to a rare birth mark.

Throughout her childhood Muhl suffered from a range of autoimmune issues and allergies. Only recently she discovered that it was actually the result of her body fighting off her own twin’s immune system.

“For more than half my life I didn’t even know I had chimera,” Muhl recently told the Huffington Post. “I was told I had a birthmark.”

“My mom was like a flower child so she had me naturally at home with two mid-wives. Her whole pregnancy she ate all fresh, healthy food, no caffeine.”

While Muhl’s family put it down to a weird birthmark and moved on with their lives, there were other signs that things weren’t quite right.

From a young age Muhl was fascinated with the idea of being a twin.

“From six or seven-years-old, I would ask my mother all the time if I was a twin. ‘Are you sure you didn’t have another baby?’ I would ask her. Many years later, my mom told me she wondered back then, ‘Where is this coming from? Why is she asking me this?’”

Muhl even insisted that her friends dress the same as her and do their hair the same as her.

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“I had a friend who was two years older who basically lived with us for eighteen years. I insisted on everything being the same with us – clothes, hair. And if she did it, I had to do it too,” she said.

Then in her early teens Muhl started getting sick all the time, except when taken to see medical professionals, they had no definitive answers for her.

“I started having autoimmune issues. I’m very sensitive to food and medication. I’m allergic to bug bites on one side of my body but not the other. My belly button piercing is on [my] twin’s side and I can wear any jewellery in it. But the earrings on my side, I can only wear white gold because my skin is very sensitive.”

Years later after extensive testing, one doctor finally figured out what was going on – Muhl had absorbed her own twin in the womb and her body was constantly trying to “fight off” the foreign system inside it.

Now that she’s aware of her condition, Muhl is trying to raise a greater awareness of chimerism.

“There’s a reason I was born this way and maybe it’s to help or inspire people,”she explained.

“I feel very grateful that my story is being shared. I have so many men and women who reach out to me. They say, ‘You make me feel beautiful’. And that’s the whole point, not just to help someone who may be a chimera but also to spread body positivity.”