MEDICAL MYSTERIES EXAMINES SOME OF THE STRANGEST CONDITIONS KNOWN TO MEDICINE Airing on "20/20," Friday, August 7 on ABC

Whether examining how a baby born with his heart outside of his body can possibly survive or why millions of women only feel pain during sex, "Medical Mysteries" reports on some of the strangest conditions known to medicine. The hour examines cases that leave scientists and doctors with unanswered questions when trying to explain the human body. "Medical Mysteries" airs on "20/20" on FRIDAY, AUGUST 7 (10:00-11:00 p.m., ET) on the ABC Television Network.

Millions of women suffer an embarrassing secret: they don't feel pleasure with sexual intercourse - they feel excruciating pain. What is almost worse than the pain, the women say, is the desperate search for a diagnosis to this mysterious condition. The average woman will go to seven different doctors before she gets a diagnosis, and many have been told their problems are psychological, that it's "all in their head." ABC News' Dr. Tim Johnson reports that a crusading doctor is unraveling the mystery, giving hope for a treatment.

And: Christopher Wall came into this world with all the right parts, except that one of them was in the wrong place. His heart was beating outside his body. More than a medical rarity, it was a mystery to doctors. Why did it happen and how could he ever survive? JuJu Chang reports.

Also: Carly was a severely autistic little girl unable to speak a word or connect to the world around her in any way. Or so everyone thought. That is until she turned 11 and something truly remarkable happened - she typed her first words: "h-u-r-t" then "h-e-l-p." John MacKenzie reports.

Plus: It's a one in a million diagnosis, a mysterious neurological disorder that attacks women in the prime of their lives: waking up one day unable to move or even walk. And it happened to Kristie Tunick in 2006. Only 29, her body began to lock up, virtually paralyzing her for hours and causing excruciating pain. Tunick was a real-life medical mystery who stumped the doctors who tried to diagnose her. Bob Brown reports on a medical mystery wrapped in a beautiful love story of Tunick and the selfless fianc� who cares for her.

Additionally: Deborah Roberts reports on people who have a medical condition called SRED, Sleep Related Eating Disorder, where they eat in their sleep. Sometime it's once, sometimes many times a night, fast asleep; the sufferers eat things as odd as cat food, coffee grounds, eggshells or soap, and don't even know they're doing it. (OAD: Aug. 2008)

"20/20" is anchored by Elizabeth Vargas and John Stossel. David Sloan is executive producer.

The hour airs in conjunction with the Hyperion book release of MEDICAL MYSTERIES: From the Bizarre to the Deadly. . . The Cases That Have Baffled Doctors.