Kelly Miller of Hagerstown, Md., has a different kind of sexual oddity, one that she was unaware of until she started to menstruate at 11 and had excruciating periods.
"Things weren't normal compared to other kids," said Miller, who is now 28. "I had a more bleeding and pain and it continued to get worse."
When she was 15, her mother took her to see the doctor who was "pretty surprised" when he discovered she had two vaginas and two uteruses, said Miller.
Having two vaginas -- a didelphic uterus -- is a rare condition that occurs in about one in 3,000 women, according to the World Health Organization.
"It is all internal," she said. "If I was standing naked with 120 other women, you wouldn't know."
Inside Miller's vaginal opening is a thin wall of skin that separates into two cervixes that lead to two separate uteruses. Her right one is dominant. The left vagina is only pencil width and is nonfunctional.
Two weeks after that first doctor visit, when Miller arrived for an ultrasound, doctors from around the country gathered to witness her anomaly.
"It wasn't really that upsetting at that point," she said. "I was so young. The unknown was more intimidating."
Miller said she wondered, "What does it mean? Is it a bad thing for me to have? Will I be OK? Am I normal?"
The doctor mentioned that she might not ever be able to have children. Each of her uteruses was 60 percent the normal size and might not accommodate the growth of a fetus, she was told. "A lot of women miscarry," she said.
He put her on a low dose of birth control pills to regulate the double monthly bleeding, even though she was not sexually active.
But in 2002, when Miller turned 19, she met her future husband. "I didn't tell him at first," she said. "I worried he would think I was weird. But there's nothing about me that would make things sexually different."
Miller soon got pregnant. Her obstetrician was "welcoming and reassuring" and closely watched her developing pregnancy, even praying with her.
At 37 weeks, Miller successfully delivered a girl, and in 2005, delivered another healthy daughter.
"The doctor said I was very, very lucky," said Miller, who went public with her condition to help others. "I wanted to show women that even if they have the condition, they can have a perfectly normal marriage, normal sexual relations and have children."
Today, Miller is a stay-at-home mother with her two girls, ages 5 and 9. As for more children, she said, "We're done. I want to enjoy the two I have."