"What do you mean? "
"Well, one Mrs. Smith has tested positive for Alzheimer's and the other Mrs. Smith has tested positive for AIDS. We can't tell which is your wife."
"That's terrible. Can we do the test over?"
"Normally, yes. But you have an HMO, and they won't pay for these expensive tests more than once."
"Well, what am I supposed to do now?"
"The HMO recommends that you drop your wife off in the middle of town. If she remembers the way home, don't sleep with her."