Question. What followeth?
Answer. That, he was conceived of the holy Ghost, born of the virgin Mary.
Question. And why was he not begotten in the usual and natural way?
Answer. Because he who came to cleanse us from our sins had to be free from sin himself. Therefore, Jesus Christ, the most pure Lamb of God, was conceived and born without sin by the miraculous work of the Holy Spirit, of the Virgin Mary.
Scripture Reference: John 1:19; 1 Cor. 7:7-8, Heb. 4:15 and 9:14; Matt. 1:23; Luke 1:31, 35