Brooke Greenberg continues to baffle her family and doctors.
At 16-years-old, Brooke weighs 16 pounds and stands 2 feet, 6 inches tall, MyFOXChicago reported. She can’t speak, but she can express frustration and happiness.
In other words, Brooke’s body and mind are that of a toddler.
“Why doesn’t she age?” Brooke’s father, Howard Greenberg said on ABC News. “Is she the fountain of youth?"
Brooke, who lives in Maryland, still has baby teeth, and her bones are those of a 10-year-old. However, her hair and nails grow consistently.
Doctors think Brooke has a genetic mutation that inhibits her growth.
“Without being sensational, I’d say this is an opportunity for us to answer the question why we’re mortal, or at least test it,” Dr. Richard Walker of the University of South Florida told ABC News. “And if we’re wrong, we can discard it. But if we’re right, we’ve got the golden ring.”
To learn more about Brooke, watch "Child Frozen in Time" at 10 p.m. Sunday, Aug. 2 on TLC.