Canonical age

In the canon law of the Catholic Church, a person is a subject of certain legal rights and obligations.

The age of reason is the age at which children attain the use of reason and begin to have moral responsibility. On completion of the seventh year a minor is presumed to have the use of reason, but mental retardation or insanity prevent some individuals from ever attaining the use of reason. The term "use of reason" appears in the Code of Canon Law 17 times, but "age of reason" does not appear. However, the term "age of reason" is used in canon law commentaries such as the New Commentary on the Code of Canon Law published by Paulist Press in 2002.

Children who do not have the use of reason and the mentally handicapped are sometimes called "innocents" because of their inability to commit sins: even if their actions are objectively sinful, they sometimes lack capacity for subjective guilt.

In the Eastern Catholic Churches, the Eucharist and Confirmation are given immediately after baptism, even to infants who do not yet have the use of reason. In Latin Rite Catholicism, Confirmation is conferred, except in danger of death, only on persons who have the use of reason; and Holy Communion may be administered to children only if "they have sufficient knowledge and careful preparation so that they understand the mystery of Christ according to their capacity and are able to receive the Body of Christ with faith and devotion." In danger of death, the Eucharist may be administered also to children who lack the use of reason, if the child can distinguish the sacrament from ordinary food and receive it reverently. This is likewise true for those who are so mentally retarded that they are not assumed ever to gain the use of reason.

...
Wikipedia