For information regarding the Catholic teaching on routine infant circumcision, please refer to the following links:
To Circumcise or Not to Circumcise published by the Catholic Health Association of the United States
From the Council of Florence:
"Therefore it (the Holy Roman Catholic Church) strictly orders all who glory in the name of Christian, not to practice circumcision either before or after baptism, since whether or not they place their hope in it, it cannot possibly be observed without loss of eternal salvation."
(Entire text of the Council can be read here.)
To summarize, as a matter of faith, the practice of circumcision has been authoritatively and irrefutably denounced by the Church from the Council of Jerusalem in the book of Acts from Scripture and several times since. Catholics are forbidden from circumcising as a practice of faith. From a medical standpoint, because no authoritative medical body recommends it as routine practice, infant circumcision without direct medical need is considered in violation of standard Catholic medical ethics.