Switched at birth.
Teenager Gwen Norbeck came on the Oakdale scene in 2005. It was revealed she had slept with Casey Hughes and was pregnant.
Since Casey was dating someone else and acted cold towards Gwen, she kept the baby's paternity from him. Will Munson, however, befriended her, helped her through her pregnancy and the two eventually fell in love.
Gwen went into premature labor, as did Will's sister Jennifer at the same time. Sadly, Gwen's boy died, but Craig Montgomery switched the babies, so she thought she was raising her son, but she was actually caring for Jennifer's.
Of course, the truth came out, including that Casey was the father, and Gwen had to say goodbye to the boy she thought of as her own. Watch that moment, as well as Casey owning up to being the father in the videos below.