PERVERSION. — It is the action or effect of perverting, that is, of corrupting, inducing someone to do what is not fitting. Generally it is said of turning someone away from the straight path; in the psychological field, perversion is the disorder or alteration of some psychic function; in pathology it is said of seeking lustful satisfaction outside the natural order (v. LUST); in the moral field, it is any aberration from good morals or right feeling in religious matters.
Therefore, forms of perversion include apostasy (v.), heresy (v.), and schism. Measures taken by the Church to prevent perversion in matters of faith and morals include provisions regarding perverse and immoral books (v. IMPRIMATUR; INDEX OF PROHIBITED BOOKS).
For the same reason, Catholics are at least actively to participate in sacred ceremonies (prayers, services, sermons, rites) performed by non-Catholics (heretics, schismatics, unbelievers) inside or outside their temples (v. COMMUNICATION IN SACRED THINGS). And it is also in part for this reason that it is illicit to ask for the Sacraments (v.) from an unworthy minister or from heretical or schismatic ministers, even when they would be able to confer them validly.
With regard to marriage, the Church openly discourages unions between Catholics and non-Catholics, even if only heretics or schismatics (canons 1060, 1070; cf. the apostolic constitution Arcanum of Leo XIII of 10 Feb. 1880). And even when granting a dispensation, the Church requires the due guarantees (canons 1061 § 2) and does not permit liturgical solemnities in the celebration of the marriage (canons 1102 § 1, 2; 1109 § 3).