Episcopate
Bishops are chosen from among the priests in the Catholic Church. Among Eastern Catholic Churches, which permit married priests, bishops must either be widowers, unmarried or agree to abstain from sexual contact with their wives. It is a common misconception that all such bishops come from religious orders. While this is generally true, it is not an absolute rule. Catholic bishops are usually leaders of territorial units called dioceses.
Only bishops can validly administer the Sacrament of Holy Orders. In Latin-rite Catholic churches, only bishops (and priests with authorization by the local bishop) may lawfully administer the sacrament of confirmation, but if an ordinary priest administers that sacrament illegally, it is nonetheless considered valid, so that the person confirmed cannot be actually confirmed again, by a bishop or otherwise. Latin rite priests with special permission of the diocesan bishop or the Holy See can lawfully administer confirmation; every Catholic priest must administer confirmation, even without permission, to children in danger of death. In Eastern Catholic Churches, confirmation is done by parish priests via the rite of chrismation, and is usually administered to both babies and adults immediately after their baptism.
Read more about this topic: Holy Orders (Catholic Church)