Astounding Medical Mysteries

Of the 100 primordial dwarfs on earth, Kristin is the oldest at the age of 26. For years, she had her doctors stumped on her condition—and now they're learning from her.

Although Kristin's brain is just a fraction of the size of an average brain, she is no less intelligent. "How is that possible?" Dr. Oz says. "It challenges all of our thinking about how we work. How can you get 100 billion neurons into your brain just like a larger brain? That's the subtlety of the human body. That's why we learn so much."

Dr. Oz brings out a replica of Kristin and Brenden's femur bones along with an average-size femur bone. "So if you compare them, there's huge differences," Dr. Oz says. "The fact that all three of these could exist together is, to me, a miracle in itself."

"That's the miracle of life," Oprah says. "How we're all alike but different."