A Riddle

On his recent trip to Great Britain, George Bush had a meeting with Queen Elizabeth. He asked her, "How does one manage to run a country so smoothly?"

"That`s easy," she replied, "You surround yourself with intelligent ministers and advisors."

"But how can I tell whether they are intelligent or not?" he inquired. "You ask them a riddle," she replied, and with that she pressed a button and said,"Would you please send Tony Blair in."

When Blair arrived, the Queen said, "I have a riddle for you to answer for me. Your parents had a child and it was not your sister and it was not your brother. Who was this child ?"

For the rest of the story .... Who was that child? .