Difference?

A guy takes his ill and aging wife in to the doctor's office.

After a full examination, the doc tells the guy it's one of two things.

The Doc says, "Well, it's either Alzheimer's disease or AIDS."

"What do you mean," the guy says. "Can't you tell the difference?"

"Well," says the Doc, "the two look a lot alike in the early stages.
Tell you what ya should do...Drive her way out into the country, kick
her out of the car, and if she finds her way back... don't have sex
with her anymore!"