After Kay McDonald and Mari Miller gave birth to their daughters in May 1951, both mothers waited anxiously for their baby girls to be bathed and swaddled.

But, when Mari Miller was handed her daughter, she told the nurse that she had the wrong baby. Her husband, Reverand Miller, assured her that the little girl must be theirs - he didn't want to embarrass the doctor.

Although Miller suspected, McDonald had no idea that for 43 years, the mothers had raised each other's daughters.

Mari Miller raised a daughter she named Marti, while Kay McDonald raised a daughter she named Sue. It wasn't until a letter written by Mrs. Miller some 43 years later, that the truth was revealed.

Listen to the emotional audio recording from the show This American Life, or read the full transcript.

[Source: Spring. St/ This American Life]