Church Teaching on Unnatural Acts in Marriage

The Church condemns the use of contraception, even in marriage, because contraception deprives sexual acts of their procreative finality. The Church condemns homosexual acts mainly because these acts “close the sexual act to the gift of life”. But unnatural sexual acts, used in the Sacrament of holy Matrimony, are just as closed to the gift of life; they are inherently non-procreative sexual acts. Such acts are so similar to homosexual acts as to deserve the same condemnation; they are “acts of grave depravity”.

Saints and Doctors of the Church Jerome, Augustine, Aquinas, Francis de Sales, and Alphonsus Liguori have all condemned unnatural sexual acts in marriage. See the articles here. But some proponents of unnatural sexual acts have claimed that the Church has no teaching on the subject. They want us to believe that, after 2000 years and countless sacramental marriages, the Church Herself, the guardian of the Deposit of Faith, has no idea whether these acts should be condemned as intrinsically evil and gravely immoral, or approved as good and holy. That claim is laughable.

The Church cannot both condemn homosexual acts and approve of the same types of acts in marriage. Such a condemnation would not only be hypocritical, it would undermine the primary reason that same-sex marriage is rejected by the Magisterium, that the sexual acts of said union are inherently closed to life. The Church cannot both condemn contracepted sexual acts for being non-procreative, and then approve of unnatural sexual acts, which are even more thoroughly non-procreative.

Moreover, every reason given by proponents to justify the use of these “acts of grave depravity” within holy Matrimony depends upon a rejection of the basic principles of ethics taught by the Church.

Magisterial Teaching

“Sexual relations are human when and insofar as they express and promote the mutual assistance of the sexes in marriage and are open to the transmission of new life.” [CDF, Considerations Regarding Proposals to Give Legal Recognition to Unions between Homosexual Persons, n. 7.]

The Magisterium teaches that sexual relations is fully and truly “human” only when these acts are “open to the transmission of new life”. But what if the couple are elderly and unable to conceive? It is a basic principle of ethics that acts are inherently licit or illicit based on the knowing deliberate choice of the act, with its ordering toward a good or evil object, regardless of whether the act attains the object toward which it is ordered. So the choice of contracepted sex is evil, even if procreation occurs due to the failure of the contraception. And natural marital relations is moral, even if procreation does not occur, due to old age.

Which sexual acts are approved under natural law, and which are unnatural, being contrary to the natural moral order as ordained by God? Natural law is not based on humans behaving like the animals in nature, but on humans behaving in a manner which is most truly human. Thus, the assertion of the CDF that sexual relations are human only insofar as they are open to new life is a natural law argument. Non-procreative sexual acts are unnatural.

“Each and every sexual act in a marriage needs to be open to the possibility of conceiving a child.” [USCCB Catechism, p. 409.]

“A marriage is only as open to procreation as each act of intercourse is, because the whole meaning of marriage is present and signified in each marital act. Each marital act signifies, embodies, and renews the original and enduring marital covenant between husband and wife.” [Pastoral letter of the U.S. Bishops, “Marriage: Love and Life in the Divine Plan”]

The basic principles of ethics require each act of a human person to be morally licit. Acts are not judged, as to their morality, as a set, but as individual knowing choices. Each and every sexual act must be open to at least the possibility of new life, that is to say, each sexual act must be inherently procreative. Unnatural sexual acts are inherently closed to life, and so they are gravely immoral. They are not procreative, not truly unitive, and not truly marital.

“The conjugal union is ordered to procreation ‘by its very nature’…. Hence no genital act of husband and wife can refuse this meaning….” [Pope Francis, Amoris Laetitia, n. 80.]

Here is the same teaching as in several other magisterial documents (above and below), but with a different wording: “no genital act of husband and wife” can refuse this meaning, the procreative meaning of marital relations. Unnatural sexual acts are unnatural because they are genital acts which refuse the procreative meaning. It simply is not possible to accept all of the magisterial teachings on marital relations, and also claim that unnatural sexual acts are somehow moral.

“The Church, nevertheless, in urging men to the observance of the precepts of the natural law, which it interprets by its constant doctrine, teaches that each and every marital act must of necessity retain its intrinsic relationship to the procreation of human life.” [Pope Paul VI, Humanae Vitae, n. 11.]

There it is again, a magisterial teaching asserting that “each and every marital act” must be intrinsically directed toward the procreation of human life. This assertion is not limited to the topic of contraception. It does not say each and every marital act must not use contraception. The reason that contraception is immoral is the deprivation of the procreative meaning, a meaning and purpose inherent to the very nature of the gift of sexuality. Any other non-procreative, or non-unitive, or non-marital uses of that gift are also intrinsically evil and gravely immoral.

Humanae Vitae asks: “Could it not be admitted, in other words, that procreative finality applies to the totality of married life rather than to each single act?” And the answer is that non-procreative sexual acts cannot be said to “merge with procreative acts of past and future to form a single entity, and so be qualified by exactly the same moral goodness as these.” [Pope Paul VI, Humanae Vitae, 3, 14.]

Can we not justify the use of unnatural sexual acts for the purpose of foreplay, the purpose of preparing for natural marital relations? The question is essentially implicitly asked and answered in Humanae Vitae. The answer is that the procreative finality must apply to “each single act”. One cannot merge a set of unnatural sexual acts, which are inherently non-procreative, with one or more procreative acts of past or future, as if this set of choices could “form a single entity” and then take its moral goodness from only the procreative acts. So a common claim of proponents of unnatural acts is refuted. Performing an unnatural sexual act in the same context as the natural act does not justify the former.

When foreplay is the purpose of an unnatural sexual act, that purpose is the intended end. But intention in no way justifies acts which are intrinsically evil, because such acts are deprived of goods required by the moral law in the object of the act. Unnatural sexual acts, used for any purpose, are still intrinsically evil because they still are inherently non-procreative and non-unitive. This is not the type of union ordained by God for marriage.

Saint Alphonsus Liguori specifically rejects the use of unnatural sexual acts as foreplay, and the use of unnatural sexual acts on the wife after natural marital relations. See his reasoning in this article here.

On the claim that an unnatural sexual act is not a sexual act at all, because it lacks climax, the USCCB teaches the following:

“Masturbation, which is deliberate, erotic stimulation often to the point of orgasm, commonly occurs together with pornography use. While popular culture largely sees it as acceptable, masturbation is always gravely contrary to chastity and the dignity of one’s body.” [USCCB, Create In Me A Clean Heart”, III. Pornography’s link to other sins]

Masturbation is still a gravely immoral sexual act if climax is lacking. Adultery is still adultery, fornication is still fornication, and unnatural sexual acts are still unnatural sexual acts if climax is lacking (just as St. Liguori specifically teaches). All these sexual sins are “gravely contrary to chastity and the dignity of one’s body”.

I should also point out that proponents of unnatural acts justify the use of completed unnatural sexual acts on the wife, at any time, before or after natural marital relations. So the claim that these acts are merely foreplay is absurd. Completed unnatural sexual acts are not foreplay, especially when done after natural intercourse. And they are not justified when, for the husband, they lack climax, just as masturbation, adultery, and fornication are not so justified.

The basic principles of ethics taught by the Church do not allow an act which is intrinsically evil, when done in isolation, to become justified when done as part of a set of acts, only some of which are moral. Neither is it possible to claim that the unnatural sexual acts are not acts. For the moral teachings of the Church consider each knowing and deliberate choice to be an act subject to morality [CCC 1749 ff.].

The intention to commit one act of natural marital relations does not justify the knowing and deliberate choice to engage in intrinsically evil sexual acts. Intrinsically evil acts are never justified by intention or circumstances [Veritatis Splendor 81]. And therefore, the occurrence of the unnatural sexual acts within the context of an act of natural intercourse does not justify the intrinsically evil acts:

“It is therefore an error to judge the morality of human acts by considering only the intention that inspires them or the circumstances (environment, social pressure, duress or emergency, etc.) which supply their context. There are acts which, in and of themselves, independently of circumstances and intentions, are always gravely illicit by reason of their object; such as blasphemy and perjury, murder and adultery. One may not do evil so that good may result from it.” [CCC 1756]

A set of lies does not become justified by including in the set one true assertion. A set of thefts does not become moral by including in the set a donation to charity. Direct abortion is not justified by the intention to save the mother’s life. Euthanasia is not justified by the circumstance that the patient will suffer greatly without it. Unnatural sexual acts can only be said to be moral by first abandoning the basic principles of ethics as taught by the Church.

Unnatural sexual acts are condemned when done by same-sex couples. The claim that the same types of acts, which are just as thoroughly non-procreative and non-unitive, become moral when done in marriage is contradictory. The Catechism of the Catholic Church teaches [n. 2357] that: Homosexual acts are “intrinsically disordered” and “contrary to the natural law” and “acts of grave depravity” because they “close the sexual act to the gift of life”. Unnatural sexual acts between husband and wife have the same intrinsic disorder. They are inherently non-procreative and are closed to the gift of life, therefore they are also acts of grave depravity, and contrary to the natural law.

It is sinful blatant hypocrisy to say to same-sex couples, “You can’t have a valid marriage because your sexual acts are non-procreative,” and then tell Catholic married couples that there is nothing wrong with using the same type of sexual acts within their marriage.

“There are absolutely no grounds for considering homosexual unions to be in any way similar or even remotely analogous to God’s plan for marriage and family. Marriage is holy, while homosexual acts go against the natural moral law. Homosexual acts ‘close the sexual act to the gift of life’.” [CDF, Considerations Regarding Proposals to Give Legal Recognition to Unions between Homosexual Persons, n. 4]

Unnatural sexual acts are just as closed to the gift of life as same-sex acts, and so the former acts are just as immoral as the latter, just as much “against the natural moral law”, and just as contrary to “God’s plan for marriage and family”.

Certainly, there are some priests and theologians who approve of these acts. But most of the time, they give no theological argument to support this position. They simply make the baseless claim, and fallen sinners who desire to commit this grave sin accept their claim as an unconscionable rationalization. But we all know what the Church on earth is like. There is always a theologian or priest, even one with a good reputation, who will justify one grave sin or another. This unfortunate truth applies to sex, contraception, abortifacients, abortion, and many other grave sins.

Casti Connubii

Unnatural sexual acts are intrinsically against nature because, as the many magisterial documents above teach, each sexual act in a marriage must be procreative. And intrinsically evil acts of any kind are never justified by intention or circumstances.

“But no reason, however grave, may be put forward by which anything intrinsically against nature may become conformable to nature and morally good. Since, therefore, the conjugal act is destined primarily by nature for the begetting of children, those who in exercising it deliberately frustrate its natural power and purpose sin against nature and commit a deed which is shameful and intrinsically vicious.” [Casti Connubii 54]

Not only the use of contraception, but also the choice to engage in unnatural sexual acts, is “intrinsically against nature”. Therefore, the Church teaches that “no reason, however grave, may be put forward” to justify the use of non-procreative sexual acts. Those spouses who deliberately choose to use the generative sexual faculty in a way that frustrates or deprives that faculty of its natural procreative power and purpose “sin against nature and commit a deed which is shameful and intrinsically vicious.” Does this apply only to contraception? No, it does not. Any use of the faculty given to human persons as a gift whose purpose is procreative, in such a way that the procreative purpose is negated, is just as shameful and just as immoral.

“Nor are those considered as acting against nature who in the married state use their right in the proper manner although on account of natural reasons either of time or of certain defects, new life cannot be brought forth. For in matrimony as well as in the use of the matrimonial rights there are also secondary ends, such as mutual aid, the cultivating of mutual love, and the quieting of concupiscence which husband and wife are not forbidden to consider so long as they are subordinated to the primary end and so long as the intrinsic nature of the act is preserved.” [Casti Connubii 59]

The use of the marital right (sexual intercourse) “in the proper manner” refers to that type of sexual act which is inherently ordered toward procreation. And the natural sexual act remains natural, even when, by “natural reasons either of time or of certain defects, new life cannot be brought forth.” But this applies only “so long as the intrinsic nature of the act is preserved.” Its intrinsic nature is its ordering toward the primary purpose of marital relations and of marriage itself: procreation. This passage necessarily implies a rejection of unnatural sexual acts. It is not solely about contraception. A couple does not use contraception if they are elderly and therefore not able to conceive. But, even then, Casti Connubii teaches that the marital act must retain its intrinsic nature, that is, its ordering toward the procreative finality. Those who are “in the married state” are required by natural law and Church teaching to “use their right in the proper manner”, so that “the intrinsic nature of the act is preserved”. And that nature is its ordering toward the procreative finality.

Pope Pius XII: Address on Fertility and Sterility

22. Yet this right, which pertains to the object and scope of the natural law, has not been assigned to the will of human persons. By the force of this law of nature, the human person does not possess the right and power to the full exercise of the sexual faculty, directly intended, except when he performs the conjugal act according to the norms defined and imposed by nature itself. Outside of this natural act, it is not even given within the matrimonial right itself to enjoy this sexual faculty fully. These are the limits to the particular right of which we are speaking, and they circumscribe its use according to nature.

25. What has been said up to this point concerning the intrinsic evil of any full use of the generative power outside the natural conjugal act applies in the same way when the acts are of married persons or of unmarried persons, whether the full exercise of the genital organs is done by the man or the woman, or by both parties acting together; whether it is done by manual touches or by the interruption of the conjugal act; for this is always an act contrary to nature and intrinsically evil.

The above magisterial teaching absolutely refutes two claims common among false teachers today. First, the claim that the wife may climax outside of the natural marital act is condemned by Pope Pius XII (n. 25). The “full exercise” refers to sexual acts to climax. And it does not matter whether acts to climax outside of the natural marital act are “done by the man or the woman, or by both parties acting together.” For “this is always an act contrary to nature and intrinsically evil.”

Second, the claim that unnatural sexual acts done about the same time as the marital act are “one act” or are thereby justified is rejected by the Pontiff. For even if this is done “by the interruption of the conjugal act”, meaning immediately afterward, it is still “contrary to nature” (i.e. unnatural) and “intrinsically evil.”

Pope Pius XII: Address to Midwives

The subject of intrinsically evil sexual acts within marriage is also discussed in Pope Pius XII’s Address to Midwives:

“41. If, in your sure and experienced judgment, the circumstances require an absolute “No”, that is to say, the exclusion of motherhood, it would be a mistake and a wrong to impose or advise a “Yes”. Here, it is a question of basic facts, and therefore not a theological but a medical question; and thus it is within your competence. However, in such cases, the married couple does not desire a medical answer, of necessity a negative one, but seeks an approval of a “technique” of conjugal activity which will not give rise to maternity. And so you are again called to exercise your apostolate, inasmuch as you should leave no doubt whatsoever that, even in these extreme cases, every preventive practice and every direct attack upon the life and the development of the new life is, in conscience, forbidden and excluded, and that there is only one way open, namely, that of complete abstinence from every performance of the natural faculty. Your apostolate in this matter requires that you have a clear and certain judgment, with a calm firmness.”

What should a married couple do if the natural marital act is not possible because pregnancy would endanger the life or health of the mother? Some married couples then seek “an approval of a ‘technique’ of conjugal activity” which, by its very nature, is non-procreative: unnatural sexual acts. The holy Pontiff answers the question, saying there should be “no doubt whatsoever that, even in these extreme case,” every non-procreative practice (discretely called a technique of conjugal activity) is “in conscience, forbidden and excluded” and the only moral choice is “that of complete abstinence” from every type of “performance” of the sexual faculty. This condemnation is not solely or even mainly in reference to contraception, but to the “technique” of unnatural sexual acts.

It may be argued that this condemnation of unnatural sexual acts only applies when the unnatural acts are not accompanied by the natural sexual act. But such an interpretation is absolutely refuted by the many previous quotes from magisterial documents excluding approval of non-procreative acts as a set with a procreative natural sexual act. The morality of sexual acts in marriage is based on “each single act”, and whether each act retains its ordering toward the unitive and procreative ends.


The arguments put forward by proponents of unnatural acts in marriage require, first of all, that we ignore, reject, or contradict the basic principles of ethics taught by the Church. When, instead, we begin with the teaching that each human act, i.e. each knowingly chosen act, must be judged on its own as to its morality, and that intrinsically evil acts are never justified by intention (the purpose of the act) or by circumstances, all these arguments fall away.

Some proponents justify their claims be reference to certain theologians and authors who approve of unnatural sexual acts in marriage. But these authors almost always offer no theological argument at all to support their assertions. By contrast, four Saints and Doctors of the Church have condemned these acts — Jerome, Augustine, Aquinas, and Liguori — and no Saints or Doctors have ever approved them. So it is not a question of which theologians have the better reputation or the better argument. The Saints and Doctors have the better reputation and the better argument, while lesser minds offer nothing but baseless claims.

Finally, all that remains is for proponents to claim that the Magisterium has no teaching on whether these acts are moral or not. That claim is thoroughly refuted by this article. None of the proponents of unnatural acts ever quotes, cites, or discusses the above teachings. If they did, they would have no way to reach a conclusion which justifies any unnatural sexual acts in marriage.

So, after reading all of the above teachings and my theological argument, on what basis would any married Catholic propose to justify these acts? If you are unsure whether an act, any act, is gravely immoral, you cannot choose the act. It is not moral to choose an act when there are substantial reasons to think that it might be an intrinsically evil and gravely immoral sin. Given the teachings of the Church and Her Saints and Doctors, there is sufficient support for the condemnation of these acts to prevent anyone from morally making such a choice.

For more on this topic, see my book:
The Catholic Marriage Bed

Ronald L. Conte Jr.
Roman Catholic theologian and translator of the Catholic Public Domain Version of the Bible.

Please take a look at this list of my books and booklets, and see if any topic interests you.

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2 Responses to Church Teaching on Unnatural Acts in Marriage

  1. Michael says:

    I have learned that you do not imitate John Martinoni, who publishes every word of those who disagree with him because John is so confident in his positions. You cannot defend your restrictive position that defines “acts” so restrictively. The fact that you have to spend this many words to make your case is all one needs to know about how you are speculating. Statements such as, “The question is essentially implicitly asked and answered in Humanae Vitae.” show that even you know the ground on which you tread is porous.

    Let me ask, is a romantic kiss on the lips between two homosexuals morally permissible? (Here, I am forced to assume that a kiss does not qualify as a “sexual act” under your mysterious definition because couples are invited to kiss at a Catholic wedding ceremony.) I assume you would agree with me that a romantic homosexual kiss is not morally permissible even if it does not result in arousal. So then why, under your faulty comparison, would a romantic kiss among heterosexuals done at a Catholic wedding at St. Peter’s be morally permissible even if it results, accidentally or not, in arousal in at least one of the two? My point is that you err by comparing the activities (movements of the body) while ignoring the context. Homosexual sexual encounters, as is true of all extramarital sexual activity, are prohibited ab initio. There is a substantial difference between foreplay that ends in the husband completing inside his wife in a non-contraceptive way and then false imitations of what is proper only to marriage.

    • Ron Conte says:

      I’m working on a book on the topic, which includes an extensive section on the opposing view. An act is a deliberate knowing choice [CCC 1749 ff]. You cannot merge several non-procreative sexual acts with one procreative sexual act, and claim that the former are justified by the latter [HV 14], as if all these choices were one act. And a husband sodomizing his wife is prohibited ab initio. It is intrinsically evil on its own, and it doesn’t become moral if it is followed by the natural act, because the end doesn’t justify the means [CCC 1753]. Also, intrinsically evil acts are never justified by intention (such as to prepare for natural relations) or context [CCC 1756]. Your comparison between a kiss at a wedding and oral sex is absurd. These are not meaningless movements of the body. And an unnatural sexual act is still a sexual act, and still immoral, even if climax is lacking, just as Saint Alphonsus Liguori teaches:
      Saint Alphonsus condemns these acts in his book “Moral Theology” which was approved at the time by the Pope himself. He is a Doctor of the Church, a Bishop, and a moral theologian.

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