The Catholic Church also regulates given or baptismal names:

  Can. 855 Parents, sponsors, and the pastor are to take care that a name foreign to Christian sensibility is not given.

It is customary for anyone receiving Confirmation to choose a patron saint, but this name is not essential to the ceremony, and not usually added to one's legal or commonly-used names.

Men and women entering consecrated religious life often receive a religious name. Sometimes their surname is suppressed. Their new name may be chosen by their institute, community or their superior. It is not uncommon to see compound names, and opposite-gendered names in usage there.