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
At Brooke's Bat Mitzvah.

"Brooke is the nucleus of our family," said dad Howard Greenberg. "What if Brooke holds the secret to aging? We'd like to find out. We'd like to help people. Everybody's here for a reason. Maybe this is why Brooke is here."

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

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