Catholic theology of sexuality

Catholic theology of sexuality, like Catholic theology in general, is drawn from natural law, canonical scripture, divine revelation, and sacred tradition, as interpreted authoritatively by the magisterium of the Catholic Church. Sexual morality evaluates sexual behavior according to standards laid out by Catholic moral theology, and often provides general principles by which Catholics can evaluate whether specific actions meet these standards.

The Catholic Church teaches that sexual intercourse has a two-fold unitive and procreative purpose; According to the Catechism of the Catholic Church, "conjugal love ... aims at a deeply personal unity, a unity that, beyond union in one flesh, leads to forming one heart and soul", since the marriage bond is to be a sign of the love between God and humanity.

Because Catholics believe God found everything He created to be "very good", the Catholic Church teaches that the human body and sex must likewise be good. Every person is created in the image of God and therefore has great dignity including their sexuality. Sexuality is not something that exists with purely biological purpose defined by personal preference; rather, it is an intimate nucleus of the person that spiritually is designed by God to unite man and woman as one-flesh - not because man and woman preferred it this way, but because God designed and created woman to be equal but different from man. Genesis describes the man’s official companion being made from a bone of his bones and the flesh of his flesh.

In cases in which sexual expression is sought outside marriage, or in which the procreative function of sexual expression within marriage is "deliberately frustrated" (e.g., the use of artificial contraception), the Catholic Church considers them a grave sin. According to the Catechism, among what are considered sins against chastity are masturbation, fornication, pornography, and homosexual practices.