There are those who go as far as to affirm that mortal sin, which causes separation from God, only exists in the formal refusal directly opposed to God's call, or in that selfishness which completely and deliberately closes itself to the love of neighbor. They say that it is only then that there comes into play the fundamental option, that is to say the decision which totally commits the person and which is necessary if mortal sin is to exist; by this option the person, from the depths of the personality, takes up or ratifies a fundamental attitude towards God or people. Now according to these authors, a change of the fundamental option towards God less easily comes about in the field of sexual activity, where a person generally does not transgress the moral order in a fully deliberate and responsible manner but rather under the influence of passion, weakness, immaturity, sometimes even through the illusion of thus showing love for someone else. To these causes there is often added the pressure of the social environment.
According to the Church's teaching, mortal sin, which is opposed to God, does not consist only in formal and direct resistance to the commandment of charity. It is equally to be found in this opposition to authentic love which is included in every deliberate transgression, in serious matter, of each of the moral laws. A person therefore sins mortally not only when his action comes from direct contempt for love of God and neighbor, but also when he consciously and freely, for whatever reason, chooses something which is seriously disordered. (Sacred Congregation for the Doctrine of the Faith: Persona Humana, 1975).