For musician Eden Atwood, there have been few signs of the dark secret concealed within her body. A secret so seemingly monstrous, Eden wasn't supposed to know.
"If my mother didn't think I should know, and my father didn't think I should know, and the doctors didn't think I should know," Atwood said, "I shouldn't let anybody else know."
What could possibly be so wrong? Throughout her life, Atwood appeared to be the picture of health. She blossomed from an adorable young girl into a striking beauty. She even became a model, an actress and an accomplished jazz singer.
As a teenager, Atwood began to sense that something was wrong.
"I was the last one not to have had her period," she admitted, "and I didn't like it one bit. And my mother was saying, you know, 'don't worry about it.' But I was worried. I was really worried."
After several tests, doctors gave her bad news. They told Atwood her ovaries were twisted and cancer-prone, and that they'd have to be removed. Worse yet, the surgery would leave her infertile. She was understandably devastated.
But there was more troubling news to come. When Atwood was just 15, her stepmother blurted out something she was never supposed to, something almost unbelievable.
"She told me, 'you know, they lied to you,'" Atwood told ABC News' Juju Chang. "'You're really half-man, half-woman.'"
Surprisingly, the cutting comment didn't sound entirely crazy to Atwood.
"It made sense," she said, "Something's weird. No one's telling the truth. I can tell something's not right. This fits. I'm a freak."
Atwood is not a freak -- nor is she half-man, half-woman. But her DNA says she's a man. That's because she has male chromosomes, an X and a Y, instead of two Xs, like most females. It's a disorder of sexual development in the womb called Androgen Insensitivity Syndrome, or AIS. It can be passed down through the mother or occur as a spontaneous mutation.
"There are probably about seven-and-a-half thousand people, women, in the U.S. with the condition," said Dr. Charmian Quigley, a pediatric endocrinologist.
Despite the male chromosomes, Quigley said, women with AIS are just that -- women.
"They have a vagina, like anybody else's," she said, "but it's basically just a pouch, it's not connected to a uterus. There is no uterus. But what they have internally is testes that you would typically find in a male."
It turns out the doctors had lied to Atwood about having twisted ovaries. She really had internal testicles.
Androgen Insensitivity Syndrome
All of us, men and women, have a mix of male and female hormones running through our systems. And as you might expect, the testes of women with AIS produce huge amounts of the typically male hormone testosterone. But here's the hitch: their bodies can't process any of it. And amazingly, they turn it into the typically female hormone estrogen, giving them much more estrogen than the average woman.
These women don't get acne, and have no body odor and minimal sweating. In essence, they are the furthest thing from a male that there could be.
So, why keep it a secret from them? Quigley explained that there was a concept that "if you told them that they had a Y chromosome, or a testicle inside them, but they were externally female, they would completely meltdown."
She even showed ABC News a 1970s medical textbook that says, "It is of no benefit to disclose that the gonads were testes instead of ovaries."
It's a lie doctors have been telling since about 1953, when the syndrome was formally identified. For Atwood, it was the discovery of that lie that shattered her self-image and drove her to sleep with many men in an effort to prove her femininity.
And as for the act of sex, it's pretty much the same. Women with AIS can have orgasms just like the rest of us. But they say the lies about their conditions can interfere with intimacy and become far more toxic than the actual diagnosis.
No one has lied to 11-year-old Kylee Whitcher. She's part of a new generation of girls with AIS who not only know everything about their male DNA, they're completely comfortable talking about it.
"I don't have ovaries, which I have to have in order to have a child," Whitcher said nonchalantly, "and I don't have a uterus, and I don't have fallopian tubes -- but really, I look like any other girl."
Whitcher's mom, Jen Cole, was honest with her daughter from the beginning, in an age-appropriate manner.
"I just told her that she was special," Cole said, "and had to adopt other people's babies that don't have mommies and daddies."
Whitcher was just 3 years old when, during a surgery to repair a hernia, doctors discovered her internal testicles. Cole admitted that it scared her at first. But after doing some research, she realized that "it wasn't that big of a deal."
It's taken more than 20 years, but Atwood is finally more comfortable talking about her long-kept secret. She shared it with Bruce Anderson, who eventually married her. But Atwood says the lies told to her about her AIS gave her intimacy issues; she and Bruce eventually divorced.
They have, however, remained close. In fact, Anderson is still often found in the kitchen, making meals with Ben, the 4-year-old son they adopted as an infant.
Thanks to hormone therapy, this woman -- with male chromosomes and no womb -- was actually able to breast-feed. Atwood said it was an incredible act that "sewed up some of the Swiss cheese of [her] soul.
"I check the box every time it comes up: Male or Female? Female, " she said confidently. "But only because the box is there."
CLICK HERE to find out more about Adrogen Insensitivity Syndrome.