Regarding the incarnation....Catholic Catechism teaches:
488. "'God sent forth his Son', but to prepare a body for him,[Gal 4:4 ; Heb 10:5 .] he wanted the free co-operation of a creature. For this, from all eternity God chose for the mother of his Son a daughter of Israel, a young Jewish woman of Nazareth in Galilee, 'a virgin betrothed to a man whose name was Joseph, of the house of David; and the virgin's name was Mary':[Lk 1:26-27 .]
The Father of mercies willed that the Incarnation should be preceded by assent on the part of the predestined mother, so that just as a woman had a share in the coming of death, so also should a woman contribute to the coming of life.[LG 56; cf. LG 61.]"
To view the context, please visit http://www.christusrex.org/www1/CDHN/creed3.html#MARY
503. "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.'[Council of Friuli (796): DS 619; cf. Lk 2:48-49.]"
To view the context, please visit http://www.christusrex.org/www1/CDHN/creed3.html#MARY
488. "'God sent forth his Son', but to prepare a body for him,[Gal 4:4 ; Heb 10:5 .] he wanted the free co-operation of a creature. For this, from all eternity God chose for the mother of his Son a daughter of Israel, a young Jewish woman of Nazareth in Galilee, 'a virgin betrothed to a man whose name was Joseph, of the house of David; and the virgin's name was Mary':[Lk 1:26-27 .]
The Father of mercies willed that the Incarnation should be preceded by assent on the part of the predestined mother, so that just as a woman had a share in the coming of death, so also should a woman contribute to the coming of life.[LG 56; cf. LG 61.]"
To view the context, please visit http://www.christusrex.org/www1/CDHN/creed3.html#MARY
503. "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.'[Council of Friuli (796): DS 619; cf. Lk 2:48-49.]"
To view the context, please visit http://www.christusrex.org/www1/CDHN/creed3.html#MARY