The answer
The Chaldean Catholic Church is affiliated to the Roman Catholic Church accepting the dogmas of the Catholic faith and the Pope of Rome as the supreme head of the church. The Coptic Orthodox Church does not accept many of the dogmas of the Roman Catholic such as the Immaculate Conception, the filioque, the purgatory, the supremacy of the Pope of Rome, etc. When one is baptized in a certain denomination he/she is baptized according to the faith of that particular Church, vowing to accept and embrace all her dogmas. Consequently, a person baptized in the Chaldean Catholic Church does not hold the same faith as one baptized in the Coptic Orthodox Church. Therefore, his/her baptism is invalid in the Coptic Church.Answered by His Eminence Metropolitan Youssef (opens in a new tab)