10. Why Christmas on December 25 and Immaculate Conception on December 8?

 December 8 celebrates the Immaculate Conception of Mary, that is, our Catholic belief that Mary, by God's grace, was conceived free of original sin. Mary's birthday is celebrated on September 8, nine months later. Jesus' conception is recalled at the Feast of the Annunciation, March 25, which is, of course, nine months before Christmas.

Many people mistake December 8, the Feast of the Immaculate Conception (of Mary) with the Annunciation, the Feast of the (virginal) conception of Jesus by the power of the Holy Spirit.