Courtesy of David Ross, here's an NPR report on another pair of switched-at-birth girls who found out too-many decades later. The reporter does extensive interviews, trying to understand how it happened, and what the effects were. (Not so good, but perhaps not totally tragic, just insanely agonizing.)
The weird thing is, one of the mothers pretty much knew from the beginning. But kept it quiet. Because her husband didn't want to embarass the doctor.
What they did -
keeping the wrong kid
to spare somebody's feelings -
leaves me reeling.