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
Brooke's Story
Scientists wonder if Brooke Greenberg, now 16, will help point the way to new discoveries about the genetics of aging. Pictured from left to right on Brooke's 12th birthday are sister Caitlin, 15; Brooke; sister Emily, 18; mom Melanie Greenberg; and sister Carly, 9.

"We love her just the way she is," said Melanie Greenberg. "We don't want to change her."

Watch Brooke's story on "20/20" FRIDAY at 10 p.m. ET. (Courtesy Greenberg Family)

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