Misconception: One Couple's Journey from Embryo Mix-Up to Miracle Baby

In February of 2009, Shannon and Paul Morell were especially eager to bring a new life into the world. After years of infertility and miscarriages they had, in 2006, finally scrimped and saved enough to have in vitro fertilization. The result? Two dear daughters had been born, and six precious embryos had been frozen.

They counted the days until they could transfer the six remaining embryos. Until the fateful day of February 17, 2009, when the clinic called. “The doctor would like to you to...