The Immaculate Conception on 8 December does not celebrate the conception of Jesus but the conception of the Virgin Mary by her mother Anne following normal sexual intercourse with husband Joachim.
Mary’s birth, after Anne’s nine month pregnancy, is observed on 8 September.
The announcement of the Virgin Mary being pregnant with Jesus without sexual intercourse was celebrated at the Annunciation on 25 March and but is also remembered in two days’ time on the Feast of Our Lady of Loreto, also called the Translation of the Holy House.
The dogma of the Immaculate Conception maintains that Mary was born free of original sin in order to preserve the purity of her future son. She was immaculate, meaning spotless and never alienated from God, because she was being prepared for her unique calling.
St John Henry Newman said: ‘She was filled with grace in order to be the Mother of God.’ This reflects God’s call of Jeremiah: ‘Before I formed you in the womb I knew you; before you came to birth I consecrated you.’