Circumcision falls under both amputation and mutilation, so it is clearly covered by this policy. Catholics generally are required to respect bodily integrity. Lack of respect for bodily integrity is viewed as a violation of the Fifth Commandment, Thou shalt not kill. Except when performed for strictly therapeutic medical reasons, directly intended amputations, mutilations, and sterilizations are against the moral law. . . . Furthermore, circumcision removes healthy and functional tissue from the body and renders the part less functional.
Circumcision is thus a non-therapeutic amputation.
Therefore, for Catholics, non-therapeutic circumcision at any age is immoral according to the teaching of the Church as expressed in the Catechism . Catechism of the Catholic Church , Liguori Publications, Liguori, MO 63057-9999, 1994.