The four prevailing cultural dogmas offer a very narrow and incomplete picture of both morality and anthropology. Utilitarianism reduces moral failure to consequences and dualism reduces the body to an irrelevant aspect for the person. Nominalism prevents the access to human nature as the common ground to find the foundation of morality. And today's version of undetermined freedom promotes a freedom from the clutches of the limitations of its own body: A freedom from human nature more than a freedom for human nature.
But, what would be the whole picture of sexual morality if we took human nature seriously?
18. Men and women are different but equal.
19. Sexual differences are there to make love, not war.
20. Ignoring sexual differences fosters unjust discrimination.
21. Our sexual desires aim at the totality of the other person.
22. Romantic love is exclusive because it is total.
23. Lust is a lack in sexual desires.
24. Unless we put our sexual desires at the service of love; we will sacrifice love for the sake of lust.
Clearly sexuality in humans and animals share the goal of reproduction, but human sexuality also reveals that if humans are naturally persons, there must be a personal component of human sexuality as well. We detect, in the emotional inclinations of being attracted to other persons, the inclinations of love to be united with the person we are attracted to and the inclination to communicate this message with the natural language of the body.
We can unfortunately also discern a contradictory inclination: The lustful inclination to make sexuality impersonal or even counter-personal.
Reason can check which ones of these natural inclinations is fulfilling and we can draw some moral principles to guide our sexual behavior: Pursue sexual honesty or aim at expressing with our sexual acts only what is true and good and avoid treating your sexuality like an object of means to other ends.
As it happens in any realistic understanding of morality, ethical principles are necessary but insufficient. We need skills that empower us to put those principles into practice. Chastity is thus the necessary skill to purify our sexual desires from lust in order to put them at the services of love.
Only when we have a complete picture of human sexuality can we ask the adequate questions about sexual morality.