This, I might add, we share with the Orthodox. Our dispute with them on the Immaculate Conception regards not whether she sinned but whether she was sanctified at her birth. As the Patriarch of Constantinople and his suffragans wrote to Pope Leo XIII in 1895:
The one holy, catholic and apostolic Church of the seven Ecumenical Councils teaches that the supernatural incarnation of the only-begotten Son and Word of God, of the Holy Ghost and the Virgin Mary, is alone pure and immaculate; but the Papal Church scarcely forty years ago again made an innovation by laying down a novel dogma concerning the immaculate conception of the Mother of God and ever-Virgin Mary, which was unknown to the ancient Church (and strongly opposed at different times even by the more distinguished among the papal theologians).
The claim that it was "unknown to the ancient Church" or to the "one holy, catholic and apostolic Church of the seven Ecumenical Councils" seems quite open to dispute... Apparently even Photios himself was a partisan of the doctrine.
Conception, not birth! My mistake.