Meet America's tallest man and its tiniest siblings. He's 7'8". They're 2'2" and 3'2". Dr. Oz explores the unique science of life on a small to grand scale. Here, Igor Vovkovinskiy, who was born with pituitary gigantism, officially breaks the Guinness World Record for America's tallest man. Also, meet Brad and Bridget, a brother and sister both affected by a rare form of dwarfism called primordial dwarfism.

Click here to watch Part 1 and learn how Igor meets the everyday challenges of his condition.


Click here to watch Part 3 and learn more about Brad and Bridget, how primordial dwarfism affects their bodies, and what they're doing to beat the odds.

After years of trying to get pregnant, doctors told Kelsi Pierce it would be near impossible for her to conceive a child. However, Kelsi got the surprise of her life when her mom volunteered to be her surrogate — and she found out she, too, was pregnant!