Consanguinity Insofar as It Is an Impediment of Marriage

I. The reasons for the established impediment are:

1. Reverence owed to blood-relatives. "Naturally a man owes a certain honor to parents, and consequently to those blood-relatives who draw their origin from the same parents from nearby... But it is manifest according to the things said above (q. 142, art. 4, and q. 151, art. 4) that in venereal acts there especially consists a certain baseness contrary to honor; whence men are ashamed concerning these things; and therefore it is unfitting that such venereal commingling should take place between such persons mutually" (St. Thomas, II-II, q. 154, a. 9).

2. The danger of lust to be forestalled. "Persons joined by blood must live together mutually; whence if men were not kept away from venereal commingling, too much opportunity of venereal commingling would be given to human beings, and thus the souls of human beings would be made too soft by lust" (St. Thomas, loc. cit.).

3. Friendship to be promoted. "For while a man takes a wife from outside, all the blood-relatives of the wife are joined to him by a certain special friendship, as if they were his own blood-relatives" (St. Thomas, loc. cit.).

4. Physical harms to be averted from offspring. Now some judge that consanguinity by itself alone produces harmful effects;¹ others deny this,² but concede that morbid qualities, which are found in families after the manner of a certain inheritance, are transmitted more easily and in a more intense degree through marriages between blood-relatives.³

¹ According to Dr. Rillet the effects of marriages of this sort are: sterility, abortion, monstrosity, epilepsy, imbecility, deaf-mutism, paralysis, etc. According to Dr. Boudin, in the city of Berlin, out of 10,000 Catholics there are found 3 deaf-mutes, out of the same number of Protestants 6, out of the same number of Jews 27. But among the latter blood-relatives are more joined in marriage, and Protestants more than Catholics, as all know (Eschbach, op. cit., p. 100; cf. Garnier, Le Mariage, p. 81; Devey, Des dangers des mariages consanguins; De Katholiek, 1884, p. 30, 173 sq.).

² So Dr. Surbled, who for the sake of argument relates these things: "The very precise observations collected on the island of Batz, isolated off Roscoff in Brittany, whose inhabitants, almost all relatives, truly form only one same family under the same bell-tower, demonstrate without reply that consanguineous unions give a strong, robust race, remarkably fruitful and endowed with longevity" (La morale dans ses rapports avec la medecine de l'hygiene, vol. I, chap. XVI).

³ Dr. Garnier: "Consanguinity must not... be confused with heredity or the transmission of diseases, affections, and constitutional defects, apparent or hidden... This danger exists for all unions tainted by any hereditary defect, for parents transmit to their children, by generation, the morbid predispositions with which they are affected, as they do their qualities and their defects, their physical and moral resemblance. But notable differences are observed in this regard in the results. In unions between unrelated persons, the reaction of contrary, opposed elements tends to neutralize and annihilate morbid germs; all great physicians have observed this, in effect, that chronic, hereditary affections, the deformities of a family, are extinguished and disappear in successive generations through well-made crossings." (Le Mariage, article "Mariages consanguins"). Dr. Surbled: "Performed between diathetic or degenerate persons, a consanguineous union is indubitably pernicious, deplorable, and can give only bad fruits; it unites weakened, sick, deviated constitutions... The grave diseases of ancestors, constitutional diatheses, as is known, have only too manifest a tendency to be transmitted in families. Now morbid consanguinity comes to strengthen this tendency and to accumulate elements of destruction in the generations which succeed one another" (loc. cit.).

II. The existence and scope of the impediment are established by these things:

1. In the direct line of consanguinity, marriage is invalid between all ascendants and descendants, both legitimate and natural (canon 1076, § 1). With regard to natural law, consanguinity certainly diriments marriage in the first degree of the direct line, and more probably in every degree. For marriage, which introduces a certain equality, is opposed to the relation of superiority and inferiority which exists between ascendants and descendants.

2. In the collateral line marriage is invalid up to the third degree inclusive (canon 1076, § 2).

With regard to natural law, consanguinity beyond the first degree does not diriment marriage.¹ Concerning the first degree itself, brother and sister, there is dispute. Several judge that such marriages are invalid, apart from the necessity of propagating the human race through the sons and daughters of Adam.² But they judge thus both because such marriages obstruct the primary end of marriage, since depraved offspring are accustomed to arise from them; and because admitted validity would give occasion for lust among persons living in the same house. Others admit the contrary, or at least call the matter into doubt, and respond that the integrity of offspring pertains only accidentally to the good of the species, to which marriage is ordered; and that the other reason does not seem so urgent that from it one may conclude to defect of validity.

As to positive law, there are those who judge that marriage between brother and sister is diriment by divine positive law. Others, however, rather deny this, because the Mosaic law has been abrogated, and the evangelical law says nothing concerning it.

Corollary. Marriage between infidels who are blood-relatives, whether in the first degree of the collateral line or in a further degree than the first degree of the direct line, is doubtfully valid. Hence if each, or one or the other, is converted to the faith, the Holy See must be approached.

3. The impediment of consanguinity was restricted by Leo XIII³ for Indians and Negroes⁴ in Latin America and in the Philippine Islands to the second degree of the collateral line. From the declaration of August 16, 1898, this also holds for all the Antilles and the other islands of the Caribbean Sea. We judge that, from the intention of the Legislator, the aforesaid disposition is governed by the law of privilege rather than by the law of a particular law, and therefore, although it is contrary to the general law, it persists.

III. Multiplication of the impediment. Before the current Code, the impediment was multiplied as often as consanguinity itself; but now the matrimonial impediment is multiplied only as often as the common stock is multiplied, or there are as many impediments as there are common stocks (canon 1076, § 2).

IV. Dispensation. The Church cannot dispense in the first degree of the direct line, since it constitutes an impediment of natural law. It is doubtful whether she can dispense in the other degrees of the direct line and in the first degree of the collateral line. In practice, she never dispenses in the aforesaid degrees. Hence canon 1076, § 3: "Marriage is never to be permitted if there is any doubt whether the parties are consanguineous in some degree of the direct line or in the first degree of the collateral line." From this it follows: 1° it can never be permitted to anyone, for example Peter, to marry either a person with whose mother he had copula at such a time before the daughter's birth that every danger of marrying his own daughter is not excluded; or a person with whose mother his father, that is, Peter's father, had copula at such a time before the daughter's birth that every danger of marrying his own sister is not excluded.⁵ 2° A Bishop or priest who can dispense in ecclesiastical impediments in danger of death or if all things are ready for nuptials cannot dispense from these impediments. In the other degrees of the collateral line the Church dispenses if a proportionately grave cause is present.

¹ Chapter 8, de divortiis.

² In this case there is not a dispensation in the law of nature, because due order requires that the good of an inferior order yield to the good of a superior order.

³ Constitution Trans oceanum, April 18, 1897.

⁴ Who come under the name of Indians and Negroes is taught by the Sacred Congregation for Extraordinary Ecclesiastical Affairs, May 24, 1898: "Under the name of Indians and Negroes, besides the Indians and Negroes themselves, are also included those who were begotten from an Indian or Negro man and a European woman, or a woman of European blood, and likewise those who were begotten from a European man and an Indian or Negro woman, and therefore are called Mixed, Mestizos, or Mulattoes, and have an absolute half of European blood. But those are not included who draw origin from Indians or Negroes only through a great-grandfather or grandmother, and who are called Quarterones, as having only a fourth part of Indian or Negro blood; and much less those who draw origin from Indians or Negroes only through a great-great-grandfather or great-great-grandmother and are commonly called Puchueles or Pucueles. Moreover, by the name of Indians and Negroes are also understood Africans, Asians, and Oceanians, provided they are not of European blood and are staying in Latin America, although they were not born there."

⁵ Pontifical Commission, June 2-3, 1918, ad 5 (A.A.S. 1918, p. 346).

“We prohibit unions of blood relatives from being made, because both divine and secular laws prohibit them. For the divine laws, treating of this matter, not only cast out those who proceed from such unions but call them accursed; while the laws call such persons infamous and repel them from inheritance. Therefore We, following Our Fathers, mark them with infamy and judge them to be infamous.” First Ecumenical Lateran Council, year 1123, canon 5.

This is against the heresy of the incestuous. Those were so called who contended that the unions of relatives were not unlawful and who reckoned the degrees of consanguinity according to the norm of civil law. Against them, Leo IX in the First Roman Synod and at Rheims, Nicholas II at Rome, Alexander II at Rome in 1063 and especially at Rome in 1065, in which he issued the Decretal which is found in cause 35, question 5, chapter 2, Urban II at the Synod of Troyes, and the Second Ecumenical Lateran Council, canon 17, defend the canonical law and doctrine: “We altogether prohibit unions of blood relatives from being made; for the statutes of the holy Fathers and the sacrosanct Church of God detest incest of this kind, which, at the instigation of the enemy of the human race, has almost passed into use.” But the Fourth Lateran Council reduced the prohibited degrees to the number four.

“In the case of an intermediate stock (of the second degree) constituted by two persons who are themselves blood relatives (in the second degree), whether there exists and must be declared in the supplicatory petition for a dispensation one impediment of consanguinity, namely, only that which proceeds from this nearer intermediate stock; or whether, in addition, there are and must be declared two other impediments arising from the more remote common stock (of the fourth degree) through the lines joined in the intermediate stock.—Response. Negative to 1; affirmative to 2.” Holy Office, 11 March 1896.

“1. When two betrothed persons stand in the equal second degree of consanguinity, and their grandfather and grandmother themselves had contracted Matrimony in the second degree of consanguinity, so that the betrothed persons are also bound in the fourth degree of consanguinity, must a dispensation necessarily be sought and obtained from a triple impediment, namely, in the second and in the double fourth degree? ... 3. When two brothers married two sisters, are their offspring bound by a double or quadruple bond of consanguinity in the equal second degree?—Response. To 1: Affirmative, as in the decision of 11 March 1896.—To 3: Only by a double impediment of consanguinity in the equal second degree.” Holy Office, 22 February 1899; M. E., vol. 1, p. 53.

835. Origin of the impediment of consanguinity.

1. From natural law itself arises the diriment impediment of consanguinity in the direct line (whether ascending or descending), and it extends not only to the first degree (between father and daughter, between mother and son), but also to all other degrees. In the first degree of the direct line, that is, between father and daughter as also between mother and son, all admit that matrimony is prohibited by natural law itself, and even barbarous peoples themselves, indeed even brute animals, are wont to recoil from a carnal union of this kind. The reason is taken both from the physical and from the moral order. For from such carnal intercourse either no offspring or weak and deformed offspring is wont to be born. Moreover, in marital and carnal union there exists equality between the contracting parties, whereas between parents and children there is not equality, but subjection and reverence due to parents. - In other degrees of the direct line matrimony is probably also prohibited by natural law because of the same reasons of physical and moral order; but several very weighty authors, such as Billuart,¹⁸⁶ Cajetan,¹⁸⁷ to whom St. Thomas¹⁸⁸ seems to favor, teach that consanguinity in the other degrees dirimes matrimony by ecclesiastical law alone. Hence, in practice, if a case should occur in which a grandfather in paganism had married his granddaughter and afterward one or the other spouse were baptized, the Holy See would have to be consulted about what must be done.

2. By ecclesiastical law alone the diriment impediment of consanguinity in all degrees of the collateral line arose in the New Testament. Thus the more probable opinion, concerning which Benedict XIV says: "There is no agreement among theologians whether matrimony between brother and sister is prohibited by natural, divine, or human law; certainly St. Thomas, Gonzalez, Pontius, Parisius, and Aversa acknowledge only a prohibition of positive law."¹⁸⁹ - The reason is that between a brother and sister, or other blood relatives of remoter degrees, there does not intervene such a relation of reverence and subjection as exists between parents and children. Then it is incongruous to say that immediately at the beginning of the world God established something contrary to natural law itself. But it is certain that the sons of Adam took their own germane sisters as wives. From this opinion it follows that, if in paganism a brother and sister contracted matrimony (provided the civil law of that region did not invalidate such a matrimony), and if afterward one or both spouses are baptized, their matrimony cannot by that very fact be declared invalid, but recourse must be had to the Holy See. - If it is a question of a matrimony to be contracted, the Supreme Pontiff never dispenses so that matrimony may be entered between brother and sister, or in the first degree of the collateral line, even if that consanguinity is not certain but only doubtful;¹⁹⁰ but he very rarely dispenses in the second degree touching the first, for example, so that a maternal uncle may marry his sister's daughter.^190a

¹⁸⁶ De matrim., diss. 7, a. 4, § 2, I say 3°.

¹⁸⁷ Comm. in 2, 2, q. 154, a. 9.

¹⁸⁸ The Angelic Doctor says: "In the intercourse of related persons there is something which is in itself indecent and repugnant to natural reason, as that intercourse should occur between parents and children, whose relationship is of itself and immediate; for children naturally owe honor to parents. Hence the Philosopher says that a certain horse, because it had been deceived so that it coupled with its mother, cast itself down as though from horror, because even in some animals a natural reverence toward parents is present. - But other persons, who are not joined according to themselves but by order to parents, do not have such indecency from themselves; rather, decency or indecency in this matter varies according to custom and human and divine law, because the use of venereal things, which is ordained to the common good, is subject to law. And therefore, as Augustine says: 'Intercourse between sisters and brothers, the more ancient it was under the compulsion of necessity, the more afterward it was made damnable when religion prohibited it'" (S. theol. 2, 2, q. 154, a. 9, ad 3). Similar things are found in Suppl., q. 54, a. 3. Certain older authors wittily refuted the opposite opinion, saying: If consanguinity in all degrees of the direct line dirimed matrimony by natural law itself, Adam, restored to life, could marry no woman, because all descended from him in the direct line.

¹⁸⁹ Benedict XIV, Epistle Aestas anni, n. XIII, October 11, 1757. Wernz-Vidal, Ius matr., n. 348, note 60 ff., strongly maintains that the impediment of consanguinity in the first degree of the collateral line arose from natural law. Several others, such as Sanchez, Suarez, Lugo, Noldin, etc., teach the same.

¹⁹⁰ Benedict XIV, loc. cit.; and Code of Canon Law, can. 1076, § 3.

^190a Instruction of the Sacred Congregation of the Sacraments, August 1, 1931 (Acta Apost. Sed. XXIII, 413).

Caia, recently converted to the faith and formerly an Anglican, is sought in marriage by Titius, a Catholic man. Caia indeed had been joined in marriage with Lucius, a cousin who was likewise Anglican; but because of his cruelty and adultery, after the first child, while still an Anglican she had sought a divorce in a civil court, which she joyfully obtained. Now, however, Caia would like to marry Titius if this is permitted to her by the laws of God and the Church; hence she asks a confessor whether anything stands in the way of the desired marriage. Hence it is asked:

1. Whom do the diriment impediments of marriage bind?

2. By what law is the impediment of consanguinity established?

3. Is it lawful to contract marriage when an impediment is doubtful?

4. What is to be said of the case?

The first question was answered above, p. 292 and the second, p. 286.

3. Is it allowed to contract marriage with a doubtful impediment?

It is not allowed to contract marriage when there is a doubt whether it is not forbidden by the natural or divine law. When the doubt is whether it is not forbidden by positive ecclesiastica' law, the marriage may take place. When the doubt is of fact, as, for example, whether the parties are not related within he prohibited degrees, a dispensation should be asked for from the bishop, who can grant it ad cautelam.¹

1 Manual of Moral Theology, vol. ii, 336.

4. The case. As Caia and Lucius were cousins, and we must presume that they were baptized, their marriage was null and void by ecclesiastical aw. A divorce has been granted in the civil court, and so, if our suppositions are correct, Caia is free to marry. However, the confessor or the parish priest should make inquiries and satisfy himself about the facts of the case. When he has done this, he should submit the evidence to the bishop and await his decision, according to the rule laid down above, p. 283.