Her name is Jackie. She is 10 years old. She loves fashion; she loves pink.
She has no idea she is about to become a pioneer.
Jackie lives in a small town in rural Ohio. Her parents, Jennifer and John, practice law in the firm her grandfather founded. It's a place long on tradition and family values.
But things are changing at Jackie's house. Six months ago, Jennifer and John decided they would allow their 10-year-old son, Jack, to start living as a girl named Jackie.
"Jackie takes a lot longer to get ready in the morning now … with the hair and the makeup," John told "Nightline" anchor Cynthia McFadden.
It wasn't an easy decision, or a quick one.
Jackie is one of a small but growing number of children who are growing up as the opposite of their biological sex. It's called transgender.
Anatomically, Jackie is male. For most of her life, she lived as a "he."
"When I look back I don't feel like we ever truly had a son. We had a daughter that was unfortunately born in the wrong body," said Jennifer.
For years, Jack had atypical interests and mannerisms for a young boy. As a toddler, he was obsessed with dancing, dress-up and Barbie dolls. He adored the color pink and enjoyed wearing his older sister's frilly, sparkly tutus. His parents introduced him to more typically male toys like cars and trucks, but those were of little interest. As he got older and his behavior remained consistent, he was teased and taunted in school.
"[There was] a little bit of an undertone of anger. … He must have felt stuck, like, 'I don't know what to do. I want to do these things, but I can't. Because everyone around me is saying I should be a different way,'" Jennifer said.
Last winter Jack started having panic attacks and behavior problems at school. Jennifer and John decided that instead of forcing him to live unhappily as a boy, they would let him live as a girl.
They have switched to female pronouns. When someone they don't know asks about their family, they say they have two daughters.
Dr. Johanna Olson runs the Transgender Youth Clinic at Childrens Hospital Los Angeles, one of the most highly regarded centers in the country for kids like Jackie. It has treated approximately 600 transgender kids.
"This idea that we're gonna support people at a young age is very, very new," Olson said.
Olson believes that the earlier in life kids make the social transition, which means living in the world as the gender they feel they are, the better these at-risk children function.
"We often ask parents, Would you rather have a dead son than a live daughter? … These kids have a suicide rate that is astronomical compared to any other group," she said.
Olson says you can't force kids to be a gender they don't think they are. Gender identity isn't a choice; it's set at birth. Kids know whether they're a boy or a girl on the inside by the age of three or four.
A week after turning 10 years old, Jack, with tears in his eyes, told his mother his secret.
"He was a little hesitant at first, then said, 'I have to tell you something.' … And he said, 'I'm -- I'm a girl. And I can't do this anymore," Jennifer said.
"I just said, It's gonna be okay. I'm so proud of her for being brave enough to say that," Jennifer added.
"Our plan was that we would make the transition slowly," John said. But within a month, Jackie wanted to attend school as a girl. At first, her parents and teachers were worried she'd be teased and ridiculed, but to everyone's relief, Jackie has had no problems fitting in and seems to have blossomed.
This fall, her parents intend to put her on puberty blockers, which will prevent her from developing into an adolescent boy.