And the angel said to her in reply, “The Holy Spirit will come upon you, and the power of the Most High will overshadow you. Therefore the child to be born will be called holy, the Son of God."
Gospel's Commentary
Today we admire the obedience of Mary. Before the Archangel, She posed a question: How can I be a mother if I do not know man? True! She and Joseph were engaged, but not married. God is our Father and we can present Him our doubts. The Archangel responded to the question of Mary and she did not "bother" him with any more questions or by asking for proof...
-Mary just answered: “I am the handmaid of the Lord. May it be done to me according to your word.”