That’s the question 16-year-old Brooke Greenberg’s father asks.  Brooke has defied the aging process in a way so unique even medical experts are baffled.

Brooke’s doctor, pediatrician Lawrence Pakula, of Johns Hopkins School of Medicine in Baltimore, Maryland, describes the child as “always a surprise” and a fascination to many of today’s top scientists.  Children who fail to develop or grow, in various ways, are rare but Brooke has proven to be perhaps the rarest of them all.

Brooke has never been diagnosed with any of the genetic syndromes or chromosomal abnormalities that are usually associated with children that fail to develop and grow normally.  She defies conventional sense, according to Dr. Richard Walker, University of South Florida College of Medicine, Tampa.  Walker says the parts of Brooke that are growing are growing as independent parts out of sync with her body as a whole.    Walker, Pakula, and Maxine Sutcliffe, a geneticist at All Children’s Hospital in St. Petersburg, Florida, have chronicled their experience with Brooke in a paper recently published in the journal, Mechanisms of Ageing and Development.  The ABC television network will include a story of Brooke’s life on the June 26 broadcast of “20/20.”

At age 16, which she turned in January, Brooke is still the size of an infant and her mental capacity is said to be that of a toddler.  The teen still has baby teeth but her bone growth is more like what would be expected at 10 years of age.  She is still unable to talk and Walker says there’ve been only minimal changes to Brooke’s brain as she’s growing up.

Brooke’s mother says she loves to shop, just like all women do, and enjoys riding in her stroller as her mother shops for Brooke’s clothes in the infants’ section of their favorite stores.  To avoid lengthy and personal explanations, when asked how old her child is, Brooke’s mother converts her years to months, saying the child is now 16 months old.

Brooke has three doting sisters, two older and one younger, who all seem to be the picture of health.