The aged professor visited his doctor for a routine checkup and everything seemed fine.
"How's your sex life?" the medic asked.
"Well," the professor replied, "not bad, to be honest. The wife isn't all that interested anymore, so in the past week I was able to pick up and bed three women, none of whom was over 30 years old."
"At your age? I hope you at least took some precautions."
"I may be old, but I'm not senile," the elderly gent said. "I gave them all a phony name."