The Virgin Birth of Christ
Catholic dogma teaches that Mary was a virgin before, during, and after the conception and birth of her Jesus."The supernatural influence of the Holy Ghost extended to the birth of Jesus Christ, not merely preserving Mary's integrity, but also causing Christ's birth or external generation to reflect his eternal birth from the Father in this, that "the Light from Light" proceeded from his mother's womb as a light shed on the world; that the "power of the Most High" passed through the barriers of nature without injuring them; that "the body of the Word" formed by the Holy Ghost penetrated another body after the manner of spirits.
CATHOLIC ENCYCLOPEDIA: Virgin Birth of Christ