At that time, Mary was about sixteen years old, and Joseph had never touched her.
One night in her bedroom she heard a whisper through her window.
"Mary, do you know how beautiful you are? You are the most lovely of all women. The Lord must have favoured you especially, to be so sweet and so gracious, to have such eyes and such lips . . ."
She was confused, and said "Who are you?"
"I am an angel," said the voice. "Let me in and I shall tell you a secret that only you must know." Philip Pullman in Guardian