A doctor with his patients

A joke about a doctor with his patients.Let us read:

A doctor had just finished a marathon shagging session with one of his patients. He was resting afterwards and was feeling a bit guilty because he thought it wasn't really ethical to screw his patients.However,a little voice in his head said, "Lots of other doctors have sex with their patients, so its not like you're the first......"This made the doctor feel a bit better until another voice in his head said,"...but they probably weren't vets."