This is remarkable, because Mary has never had sex. She and Joseph have not even spent very much time alone, but they are pledged to each other and their wedding feast has been planned.

She has never even kissed a man. She is a virgin, yet she is pregnant. Miraculous! On the other hand, Joseph suspects that Mary has cheated on him and had sex with another man. He knows he will have to break their engagement, but he decides to do this quietly. Mary understands that it is God, in the Person of the Holy Spirit, who has made her pregnant.