Buckingham Palace has announced that HRH Prince William, the Duke of Cambridge, and Catherine, the Duchess of Cambridge, are expecting their first child. The announcement follows extensive public and media speculation about when William and Kate would have a baby. The guessing game began almost immediately after the couple said, "I do." Due to a change in the monarchy's rules, the couple's firstborn will someday be the heir to the British throne, regardless of the baby's gender. With a royal baby on the way, a look back at the William and Kate's childhoods and romance. Roll over each photo to see when it was taken, and for more info: