Jen Bricker was born without legs, but that didn't stop her from playing several sports and pursuing her love of gymnastics - a passion that led her all the way to the Junior Olympics, where she competed as a power tumbler. Today, as an adult, Bricker enjoys a successful career as a professional acrobat and aerialist; she's toured the world with Brittany Spears and worked at Disney World.

Adopted as an infant from a Romanian immigrant family, Bricker grew up idolizing champion gymnast Dominique Moceanu.

"I wouldn't shut up about her. Dominique! I knew she was Romanian. I knew we looked alike. Her biggest fan!" Bricker said.

PHOTOS: Dominique Moceanu Through the Years

What it took Bricker years to realize was that Moceanu wasn't just her idol - she was also her sister. Gymnastics, it seemed, ran in the family.

Bricker was born when Moceanu was six years old. Moceanu's parents gave the newborn up for adoption immediately, and she was taken in by an Illinois family who Bricker says treated her the same as their three sons.

"My parents made me feel everything but handicapped growing up. Handicapped wasn't even a word we used," she said.

When she was 16, Bricker's adoptive parents revealed to her the identity of her biological parents and her famous older sister. Four years later, Bricker sent a letter to Dominique, ready to make a connection.

For Moceanu, who was weeks away from giving birth to her first child, news that she had another sibling came as the shock of her life. And the fact that Jen Bricker didn't have legs stunned her even further.

"Here I was thinking, 'You did gymnastics. You did volleyball.' I was like, 'Who is this girl?'" Moceanu said.

Now the two young women and younger Moceanu sister Christina are working to make up for lost time.

"It's so much fun every time the three of us get together," Bricker said, "And I can't believe this crazy life is my crazy life. And by crazy, I mean awesome!"

Watch more on Moceanu and Bricker on the latest full episode of "20/20? online.