If a married couple used a permanent birth control without knowing it’s sinful, what should they do once they find out? Should they try to reverse it? What if it’s irreversible?
By “permanent birth control,” I assume you are referring to one of the methods of sterilization. Although a couple may try to reverse the sterilization if they wish to do so (and can obtain information on reversals from One More Soul), the Church does not require that they do so, in part because sterilizations oftentimes are irreversible. All that is required is conversion of heart, repentance, and confession.