A certain Mr. Smith went out with his son one day. While they were crossing the road a car hit them. Mr. Smith died instantly but his son was badly injured. The ambulance came and took his son to the hospital. The doctor came and said: "I can't operate on him he's my son."
How can that be???
Answer: The doctor was his mom and she can't operate on him because family members get very nervous when they operate on other family members.