Why did the Vatican reject the titles "Mediatrix" and "Co-Redemptrix" for Mary?

The Church alone has authority to define titles for the Blessed Virgin. Individual devotions or papal references do not make doctrine. The Vatican clarified that these titles, though used in devotion, can lead to theological confusion if not explained precisely. In their minimalist sense, they are orthodox. Mary is “Mediatrix” because she freely cooperated with grace and brought the Savior into the world. She is “Co-Redemptrix” in the sense that she united her will with Christ’s redemptive mission, standing at the Cross and consenting to His sacrifice. In the maximalist sense, however, where all graces must pass through her hands or she is seen as an intrinsic partner in redemption, the terminology risks undermining Christ’s unique mediatorship. Scripture and the Fathers never present Mary as a parallel redeemer. The Church wishes to protect Christ’s absolute role as sole Mediator while still honoring Mary’s subordinate and participatory role. The correction safeguards clarity without diminishing her dignity.