Brooke Greenberg is the size of an infant, with the mental capacity of a toddler.
She turned 16 in January.
"Why doesn't she age?" Howard Greenberg, 52, asked of his daughter. "Is she the fountain of youth?"
Such questions are why scientists are fascinated by Brooke. Among the many documented instances of children who fail to grow or develop in some way, Brooke's case may be unique, according to her doctor, Johns Hopkins School of Medicine pediatrician Lawrence Pakula, in Baltimore.