In the rare CPS case I'm involved in, one of the issues we are trying to determine is the identity of the father of a newborn that is in protective custody. Mom (we know who she is) said it was Mr. X. He denied it, so a DNA test was done and Mr. X was right - not the father.
Mom then told us it had to be Mr. Y. Mr. Y denied it, so we DNA test him. Just saw this report roll across my desk: "The alleged father is excluded from paternity."
Man, this is getting tricky.