Mary was used of God as the host to bring forth the body of Jesus’ humanity. When the angel told Mary that she would conceive and have a son, she replied, “How shall this be, seeing I know not a man (Luke 1:31-34)?” The angel responded by saying, “The Holy Spirit shall come upon thee, and the power of the Highest shall overshadow thee: therefore also that holy thing which shall be born of thee shall be called the Son of God (Luke 1:35).”
Article Reference: Only Begotten Son