A police officer pulls over this guy whose car had been weaving all over the place. He goes up to the guy's window: "Sir, I need you to blow into this breathalyzer tube."
"Sorry officer," says the guy, "I can't do that. I am an asthmatic. If I do that, I will have a really bad asthma attack."
"Okay, fine. I need you to come down to the station to give a blood sample."
"I can't do that either. I am a hemophiliac. If I do that, I will bleed to death."
"Well, then we need a urine sample.""I'm sorry officer, I can't do that either. I am also a diabetic. If I do that I will get really low blood sugar."
"All right, then I need you to come out here and walk this white line."
"I can't do that, officer."
"Because I am too drunk to do that."