In 1975, Teresa Wall gave birth to a baby boy who was born with Ectopia cordis, a rare birth defect in which the heart is literally exposed, sitting on the outside of his chest. Wall recalls a normal pregnancy with no problems. It wasn't until after she had given birth to Christopher that doctors discovered something was wrong.
Watch the full story on "20/20" FRIDAY at 10 p.m. ET
(Courtesy of Teresa Wall )