It kills more than breast, colon and pancreatic cancer combined. But a diagnosis doesn’t have to be a death sentence. Click here to take Dr. Oz's Kick the Habit challenge and promote healthy lungs.

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Animation produced by Visible Productions Inc.

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!