Q. 1. Why do Catholics wear and bless religious medals?
A. 1. In summary, the wearing of a medal that represents a Patron Saint is an expression of faith. The blessing of such a medal acknowledges the approval of the Catholic Church to allow the medal as a sacred symbol of the supernatural protection offered directly by our Lord, Blessed Mother or a saint. This blessing sets apart the medal as an expression of faith rather than an item of worship that has pagan roots.
A religious medal is never worn as a "charm," but rather as a constant physical reminder of the love and fidelity that we share with Almighty God and the communion of saints. The Catholic is very clear in its teachings, whether a religious medal is blessed or not, it has no built-in power. Such a belief is superstitious and condemned by the Catholic Church.
In the early days of the Church, there were many pagan practices in the community. The Catholic Church implemented many spiritual practices to combat those pagan practices. The wearing of religious medals was one such practice. Medals were used to remind the believers of Jesus, Mary, the Sainst, Shrines they had visited or even their having received the Sacrament of Baptism. Religious medals served as reminders to Catholics to pray, to perform acts of charity, to show reverence to God or the Lord Jesus, etc... Religious medals containing the images of Saints Peter and Paul were found in graves dating back to the second century. The blessing of religious medals did not commence until Pope Pius V implemented this practice in the 1500s. Religious medals are blessed by the priests of the Catholic Church.