The Girl Who Doesn't Age

Researchers wonder if 16-year-old toddler might hold genetic key to why we age.

Brooke's Story

Brooke's Story
Girl Who Doesn't Grow
Girl Who Doesn't Grow
Girl Who Doesn't Grow
Girl Who Doesn't Grow
Girl Who Doesn't Grow
Brooke's Story
Brooke's Story
Girl Who Doesn't Grow
Girl Who Doesn't Grow
Girl Who Doesn't Grow
Brooke at 13 with her younger sister Carly, 10, who said it no longer seems strange to have an older sister who is still essentially an infant.

"As I got older, she was just like another little sister to me," she said. (Courtesy Greenberg Family)

ABC News on Facebook