Morality and Eugenics
An Address of Pope Pius XII to the Seventh International Hematological Congress in Rome.

Official Documents
Pope Pius XII
Reproduced with Permission
The Pope Speaks

The Seventh International Congress on Hematology, which has gathered together in Rome more than a thousand specialists from different countries, is the occasion, gentlemen, of this visit. We are very pleased, and cordially welcome you. Your congress was preceded by the International Congress on Blood Transfusion, which We have also had the pleasure of addressing.1

A quick glance at the subjects listed in your program suffices to show the many different problems faced by hematology today. Among the subjects treated in the general sessions, We note questions concerning immuno-hematology, hemorrhagic illnesses, leukemia, the spleen and the reticular endothelial system, anemia, and the use of radioactive isotopes in hematology. There were also symposia at which papers were read and discussed. You have thus had an opportunity to increase your scientific knowledge and to apply it better in everyday life to the individuals and families for whom this acquisition of knowledge is eventually destined.

It can be said that problems of blood, inherited from past generations, and of which men are very conscious today -- with astonishment and at times even fear -- have a universal character that amply justifies your efforts and emphasizes, among other things, the broadly international character of your congress.

Attempts at a Solution

A book We mentioned in Our earlier address on the subject of genetic consultation (Sheldon Reed, Counseling in Medical Genetics2) points out the various solutions which are currently envisaged for problems of defective heredity.

Artificial Insemination

It is there reported that, since the discovery of the technique of artificial insemination, "semi-adoption" has been used on a large scale for having children when the husband is sterile or when the couple has discovered that he is the carrier of a dangerous recessive gene. Where the adoptive father has doubts regarding the legitimacy of the child which his wife has borne by this method, there is a simple remedy: legal adoption. A scientific report published in 1954 emphasizes that couples who suspect one another of sterility tend to want to determine which one of them is at fault by turning to voluntary adultery. To prevent tragic experiments of this sort, a clinic on problems of fertility can be of great help.

Another typical case occurs when a woman turns to genetic consultation because she knows she is the carrier of a hereditary sickness, and, since she cannot consent to techniques for preventing conception, intends to submit to sterilization.

The first case mentioned above envisages, as a solution to the husband's sterility, artificial insemination, which evidently presumes a donor, unknown to the couple. We have already had an opportunity to take a stand against this practice in the address delivered to the Fourth International Congress of Catholic Doctors on September 9, 1949. We absolutely condemned insemination between people who are not married to one another, and even between spouses.3

We returned to this question on May 19, 1956, in Our address to the World Congress on Fertility and Sterility4; We condemned once again all types of artificial insemination, on the ground that this practice is not included among the rights of married couples and because it is contrary to the natural law and Catholic morals. As for artificial insemination between unmarried persons, We declared in 1949 that this practice violates the principle of the natural law that new life may be procreated only in a valid marriage.

Voluntary Adultery

Solution by voluntary adultery is patently immoral, regardless of any biological, eugenic, or legal ground on which its justification is attempted.

A married person cannot assign his conjugal rights to a third person, and any attempt to renounce these rights is invalid and can draw no support from the juridical axiom "volenti non fit iniuria."5


Sterilization, either of the person or of the act alone, has also been advanced as a solution. On biological and eugenic grounds these two methods now have many proponents; they are growing in favor because of new drugs which are more effective and convenient to use.

The reaction of some groups of theologians to this state of things is symptomatic and quite alarming. It reveals a deviation of moral judgment, along with an exaggerated haste to revise commonly accepted positions in favor of new techniques. This attitude comes from a praiseworthy intention, which in order to help those in difficulty, refuses to exclude too quickly new possibilities of solution. But this effort at adaptation is applied here in an unfortunate way because certain principles either are misunderstood or are given a meaning or implication which they cannot have. The Holy See then finds itself in a situation similar to that of Blessed Innocent XI who was more than once obliged to condemn theses on morality advanced by theologians animated by imprudent zeal and short-sighted temerity.6

Several times already We have taken a position on the subject of sterilization. We have stated, in substance, that direct sterilization is not authorized by man's right to dispose of his own body and cannot be considered a valid way to prevent transmission of an hereditary disease.

"Direct sterilization," We said on October 29, 1951, "that is to say, sterilization which aims, as a means or as an end, at rendering procreation impossible, is a grave violation of the moral law and is therefore illicit. Nor has public authority the right to permit it on any pretext, much less to prescribe it or to have it carried out on innocent persons. This principle has already been announced in Casti connubii, Pius XI's Encyclical on marriage.

"When, about ten years ago, sterilization began to be more widely applied, it became necessary for the Holy See to declare expressly and publicly that direct sterilization, permanent or temporary, of a man or a woman, is illicit by virtue of the natural law from which the Church herself, as you know, has no power to dispense."7

By direct sterilization We mean an act whose aim is to make procreation impossible whether this is intended as a means or an end; but We do not apply the term to every act which, in fact, renders procreation impossible. Man does not always intend to produce the consequences of his acts, even though he has foreseen them. Thus, for example, the removal of diseased ovaries entails as a necessary consequence the impossibility of procreation, but this impossibility may not be intended either as an end or as a means.

In Our discourse of October 8, 1953, to a congress of urologists,8 We explained these matters in detail. The same principles apply to the present case and prohibit one from regarding as licit the removal of glands or of sexual organs for the purpose of impeding the transmission of defective hereditary characteristics.

Impeding Ovulation

It also answers the question that is often discussed today among doctors and moralists: Is it licit to impede ovulation by pills used to remedy undue reaction of the uterus and the organism, when this medicine, while impeding ovulation, also renders fecundation impossible? Is its use permitted to married women who, in spite of this temporary sterility, desire to have relations with their husbands?

The answer depends on the intention of the person. If a woman takes such medicine, not to prevent conception, but only on the advice of a doctor as a necessary remedy because of the condition of the uterus or the organism, she produces indirect sterilization, which is permitted according to the general principles governing acts with a double effect. But a direct and, therefore, illicit sterilization results when ovulation is stopped to protect the uterus and the organism from the consequences of a pregnancy which it is not able to sustain. Some moralists contend that it is permissible to take medicines with this latter intention, but they are in error.

It is likewise necessary to reject the view of a number of doctors and moralists who permit these practices when medical indications make conception undesirable, or in other similar cases, which cannot be discussed here. In these cases the use of medication has as its end the prevention of conception by preventing ovulation. They are instances, therefore, of direct sterilization.

A Misapplied Principle

In an attempt to justify such sterilization, a principle of morality, correct in itself but badly interpreted, is often cited: "licet corrigere defectus naturae."9 And since in practice it suffices, for the application of this principle, to have a reasonable probability, it is maintained that there is a question in the present case of correcting a natural defect.

If this principle had an absolute value, eugenics could, without hesitation, use drugs to stop the transmission of a hereditary defect. But it is still necessary to examine the means by which natural defects are corrected and to avoid the violation of other principles of morality.

The "Rhythm System"

It is also suggested that contraceptives and the Ogino-Knaus method10 be used to prevent the transmission of hereditary defects.

Some experts in eugenics who condemn their use absolutely when there is simply a question of giving rein to passion, approve of both these systems when there are serious hygienic indications. They consider them a less serious evil than the procreation of tainted children. Even if some approve of this position, Christianity has followed and continues to follow a different tradition.

Our Predecessor, Pius XI, explained the Christian position in a solemn way in his Encyclical Casti connubii of December 31, 1930. He characterizes the use of contraceptives as a violation of natural law; an act to which nature has given a capacity to produce new life is deprived of that capacity by a human will: "quemlibet matrimonii usum," he wrote, "in quo exercendo, actus, de industria hominum, naturali sua vitae pro creandae vi destituatur; Dei et naturae legem infringere, et eos qui tale quid commiserint gravis noxae labe commaculari."11

On the other hand, to take advantage of natural temporary sterility, as in the Ogino-Knaus method, does not violate the natural order as does the practice described above, since the conjugal relations comply with the will of the Creator. When this method is used for proportionately serious motives (and the indications of eugenics can have a serious character), it is morally justified.

We have spoken on this subject in Our address of October 29, 1951, not to expound on the biological or medical point of view, but to allay the qualms of conscience of many Christians who used this method in their conjugal life. Moreover, in his Encyclical of December 3 1, 193 0, Pius XI had already formulated the position of principle: "Neque contra naturae ordinem agere ii dicendi sunt coniuges, qui lure suo recte et naturali ratione utuntur, etsi ob naturales sive temporis sive quorundam defectaum causas nova inde vita oriri non possit."12

We stated in the discourse delivered in 1951 that married couples who make use of their conjugal rights have a positive obligation; in virtue of the natural law governing their state, not to exclude procreation. The Creator, in effect, wished human beings to propagate themselves precisely by the natural exercise of the sexual function. But to this positive law We applied the principle which holds for all the others: that these positive laws are not obligatory to the extent that their fulfillment involves great disadvantages which are neither inseparable from the law itself nor inherent in its accomplishment, but which come from another source and which the law-maker did not intend to impose on men when he promulgated the law.

Adoption of Children

The last method mentioned above and on which We wish to express Our opinion is that of adoption.

When parents who wish to have a child must be advised against natural procreation because of hereditary defects, one may suggest that they adopt a child. It has been proved that this advice generally produces happy results and gives happiness, peace, and serenity to the parents.

From a religious and moral point of view, adoption raises no objections. It is an institution recognized in almost all civilized states. Although certain laws contain morally unacceptable demands, this does not affect the institution itself. From the religious point of view, it is necessary that the children of Catholics be adopted by Catholics, for, in practice, parents generally will impose their own religion on adopted children.

Answers to Questions

After having discussed the solutions that are currently proposed to problems raised by hereditary defects, We have still to answer the questions you have asked Us.

These questions are all inspired by a desire to clarify the moral obligations arising from those findings of eugenic studies which can be regarded as certain.

There is question, in the various cases under discussion, of a general obligation to avoid all more or less serious danger or damage to the interested party, his spouse, and his descendants. This obligation is proportionate to the seriousness of the possible damage, to its greater or less probability, to the intensity and proximity of the harmful influence exercised, to the seriousness of the reasons that one has for performing the dangerous acts and for permitting their pernicious consequences.

These questions are for the most part questions of fact to which only the interested party, the doctor, and the specialists they consult can give an answer. From the moral point of view it can be said in general that a person has no right to disregard real risks of which one is aware.

Advisability of Blood Tests

According to this basic principle, one can reply affirmatively to the first question which you ask: Should one advise, in general, a prenuptial examination and, in particular, a blood test with respect to Italy and the Mediterranean Basin?

This examination is advisable and, if the danger is really serious, may even be made obligatory in certain regions or localities. In Italy, in the entire Mediterranean Basin, and in countries which receive groups of emigrants from these countries, special attention must be given to the "Mediterranean hematological sickness."

The moralist will avoid a categorical yes or no in individual cases. Only a study of all the facts of a given case will permit one to decide whether he is faced with a serious obligation.

To Marry or Not

You also asked whether it is permitted to advise against the marriage of a couple where the blood test reveals the presence of the Mediterranean sickness.

When a subject is the carrier of the Mediterranean hematological illness, one may advise him against marriage but one cannot forbid it. Marriage is one of the fundamental human rights, the use of which may not be prevented.

If it is difficult at times to understand the general point of view of the Church, this is because the underlying concept which Pius XI expounded in the Encyclical on marriage, Casti connubii, has been lost sight of: Man is created, first and foremost, not for this world or for his life in time, but for heaven and eternity. This basic principle seems foreign to the concerns of eugenics. Still, it is applicable; it is, indeed, the only completely valid one.

Pius XI also stated, in the same encyclical, that, even if a couple is, in spite of everything, incapable of having healthy children, no one has the right to prevent them from marrying or from implementing their legitimately contracted marriage.

In practice, it will often be difficult to make the two points of view -- that of eugenics and that of morality -- coincide. But to guarantee objectivity in the discussion, each must know the point of view of the other and be familiar with his reasons.13

To Have Children or Not?

The same principles give an answer to the third question: If, after marriage, one discovers the hematological Mediterranean sickness in the couple, is it permissible to advise them against having children?

You may advise a couple not to have children but you cannot forbid it. On the other hand, it remains to be seen what method the adviser (whether he is a doctor, a hematologist, or a moralist) will suggest to them. Specialized works on the subject provide no answer leaving the responsibility of deciding to the couples. But the Church cannot be satisfied with this negative attitude. She must take a position.

As We have explained, there is no objection to complete continence, to the Ogino-Knaus method, or to the adoption of children.

Is the Marriage Valid?

The following question concerns the validity of the marriage contract between couples who are carriers of the hematological Mediterranean illness: If the spouses are unaware of their condition at the time of their marriage, can this be reason for the nullity of the marriage? Aside from cases in which a party has laid down as a condition (Canon 109214) the absence of all hereditary disease, neither simple ignorance, nor fraudulent hiding of an hereditary defect, nor even positive error which would have halted the marriage if it had been known, is sufficient to render a marriage invalid.

The object of the marriage contract is too simple and too clear for one to claim ignorance. The ties contracted with another person must be presumed voluntary because of the sanctity of marriage, the dignity of the spouses, and the security of the children; the contrary must be proved with clarity and certainty. A grave error inherent in the contract (Canon 108415) may be undeniable, but this does not prove the absence of a real intention to contract marriage with a determined person. What is decisive in the contract is not what one would have done if one had known a certain circumstance, but what one in reality desired and did because he actually did not know this circumstance.

In your seventh question, you ask if one can consider the "Rh situation" as a reason for the nullity of marriage when it has caused the death of children from the first pregnancy?

You assume the couple did not intend to contract to have children who would be the victims of an early death because of an hereditary trait. But the simple fact that hereditary defects lead to the death of children does not prove the absence of a wish to consummate a marriage. This situation is obviously tragic, but such reasoning depends on a consideration that does not apply.

The object of the matrimonial contract is not the child, but the performance of the natural matrimonial act, or -- more precisely -- the right to perform the matrimonial act. But this right is completely independent of the hereditary traits of the begotten child and of its capacity to live.

What Advice in the "Rh Situation"?

In the case of a couple in the "Rh situation," you have also asked, is it always permitted to advise against procreation or is it necessary to wait for a first incident?

Specialists in genetics and eugenics are more competent than We are in this area. It is a question of fact which depends on numerous factors of which you are competent judges. From the point of view of morals, it suffices to apply the principles which We have explained above, with certain necessary distinctions.

Marriage of Kin

Finally, you ask if it is permissible to publish technical data showing the inherent dangers of marriage between kinsfolk. Without any doubt, it is useful to inform the public of the serious risks which marriage of this kind entails. One must also take into account the gravity of the danger in order to judge the moral obligation.

The Road to Progress

With wisdom and perseverance you are attempting to explore all possible solutions to the many difficult situations. You ceaselessly try to prevent and cure human suffering and misery. Even if there is need for greater accuracy and some modification at certain points, this does not detract from the incontestable merit of your work.

We are pleased to encourage this work. We deeply appreciate the active and serious cooperation which allows various opinions to be expressed freely but is not stopped by negative criticism. That is the only open road to real progress, not only for the acquisition of new theoretical knowledge but also for clinical application.

May you continue your work with courage and with a constant desire to safeguard the high spiritual values which alone can worthily crown your efforts.

In token of divine favor and Our goodwill, We accord to you and to your dear ones Our Apostolic Blessing.


1 See The Pope Speaks 6.4 (1960): 388. [Back]

2 Philadelphia and London: W.B. Saunders Company, 1955 - NCBQ Ed. [Back]

3 Discorsi e Radiomessaggi, XI, 223-25. [Back]

4 Ibid. XVIII, p. 217. English translation in The Pope Speaks 3.2 (Autumn 1956):191-197. [Back]

5 "One who consents receives no injury." - TPS Ed. [Back]

6 Cf.Denzinger,nn. 1151-1216; 1221-1288. [Back]

7 Discorsi e Radiomessaggi, XIII, 342. [Back]

8 Ibid., XV,373-379. [Back]

9 "It is licit to correct natural defects." - TPS Ed. [Back]

10 Commonly called the "rhythm system." - TPS Ed. [Back]

11 AAS 22 (1930) 559-560. "Any use of marriage in the exercise of which the act, by human efforts, is deprived of its natural efficacy for procreating life, infringes upon the law of God and of nature, and those who perform such an act sin seriously." - TPS Ed. [Back]

|2 AAS 22 (1930) 561. "It must not be said that those spouses act contrary to the order of nature who utilize their rights properly and in a natural manner, even though a new life cannot be engendered thereby, for some natural reason, such as the time or some defect." - TPS Ed. [Back]

13 Cf. AAS22 (1930) 564-565. [Back]

14 This and subsequent references cite the 1917 code of canon law. In the 1983 code of canon law, see Canon 1102. Cross-references to the 1983 Code can be found in The 1917 PioBenedictine Code of Canon Law in English Translation with Extensive Scholarly Apparatus, Edward N. Peters, curator (San Francisco: Ignatius Press, 2001 - NCBQ Ed. [Back]

15 In the 1983 Code of Canon Law, see Canon 1099 - NCBQ Ed. [Back]