§503
Creed › … › Paragraph 2. "Conceived by the Power of the Holy Spirit and Born of the Virgin Mary"
Mary's virginal motherhood in God's plan
Mary's virginity manifests God's absolute initiative in the Incarnation. Jesus has only God as Father. "He was never estranged from the Father because of the human nature which he assumed. . . He is naturally Son of the Father as to his divinity and naturally son of his mother as to his humanity, but properly Son of the Father in both natures."
Source: Catechism of the Catholic Church (Vatican.va)