Eternal Youth, Biological Immortality Secret? 8-Year-Old Girl Who Looks Like a Baby Could Hold Key[VIDEOS]

At 8 years old, Gabby needs to be cared for like a baby. Her parents change her diapers and feed her frequently. Her mother, Mary Margaret Williams, said Gabby's skin and hair hasn't changed much in all of 8 years. Gabby still has baby-smooth skin and fine hair.

Gabby grew taller, according to Ms. Williams in an interview with ABC News. The tiny eight-year-old wears size 3-6 months clothes since she became a little taller.

Gabby is one of the few people in the world with the condition that kept them from aging like the average human being. Scientists have yet to name this type of condition since it is rare.

Scientists have previously found 2 more people with similar symptoms. The TLC network featured Gabby's story along with Nicky Freeman, a 40-year-old Australian man who looks like a 10-year-old. The documentary special was shown on TLC back in 2011.

The mysterious condition was also discovered on a 31-year old woman in Brazil who looks like a toddler and a 29-year-old man in Florida who appears to be a toddler. They will also be featured in TLC's follow-up special.

The documentary will also show medical researcher Richard Walker as he hunts for clues and investigates what these people who don't seem to age the normal way have in common. These people could help explain human immortality and reveal the secret to eternal youth.

Mr. Walker explained that physiological change or developmental inertia is critical for human growth. If that process is missing, humans could not develop. In human development, the parts of the body should change together or else there would be chaos.

Mr. Walker believed he has discovered one of the genes responsible for the physiological change. He said if scientists could find the gene, it could be "silenced" in young adulthood to stop developmental inertia. Once the gene's off switch can be found, Mr. Walker said a person could become biologically immortal in a state of perfect homeostasis.

Mr. Walker made it clear this doesn't mean not dying but simply remain younger-looking despite the number of years added to age. A biologically immortal person can still die but he or she would not experience the effects of aging.