Consanguinity and its degrees

589. Nature of the Impediment. The impediment of consanguinity consists in this, that persons consanguineous in some certain degree cannot validly enter matrimony with each other.

a. Consanguinity is the nearness of persons descending by natural generation from the same proximate stock; therefore it arises from participation of the same blood. It is said proximate: for those who descend from a common remote stock (beyond the third generation) are no longer accustomed to be called consanguineous.

b. Consanguinity is legitimate if it arises from legitimate matrimony, and illegitimate if it arises from fornicary union; it is simple if it arises from only one source, and multiple if it arises from a double or multiple source.

c. It is clear that an impediment of matrimony arises equally from legitimate and from illegitimate consanguinity. Moreover, with regard to consanguinity which constitutes an impediment of matrimony, it makes no difference whether both parents or only one parent is common.

590. Declarations. In order that the impediment of consanguinity be rightly understood, three things must be explained: what stock is, what line is, what degree is.

1. Stock is said to be that person from whom others descend by natural generation, and in whom they come together as in a first root. Thus brothers have their father as stock; the children of two brothers have their grandfather as stock.

a. Ordinarily two persons, namely the parents, constitute the common stock; but it can also happen that one person constitutes it (whether man or woman), if this person had offspring not with one person but with several.

b. Because those born from the same stock share the same blood, they are called consanguineous. Consanguineous persons in the first degree of the collateral line are full or not full, according as they have both parents or only one parent in common. Those not full are called uterine if they have the same mother but a diverse father, and they are called consanguineous only if they have the same father but a diverse mother.

2. Line is the series of persons descending from the same stock through various generations. Line contains diverse degrees and is twofold, direct and oblique.

a. Direct line is the series of persons of whom one descends from the other, whether immediately, as a son from parents, or mediately, as a grandson from grandparents. Direct line is divided into two, one of which is of ascendants, from whom someone has origin, namely father, grandfather, great-grandfather, etc.; the other is of descendants, who have origin from someone, namely son, grandson, great-grandson, etc.

b. Oblique line (collateral, transverse) is the series of persons of whom one does not descend from the other, but nevertheless all have a common stock, as brothers, cousins.

The collateral line is either equal, if the persons placed in each line are distant from the common stock by the same degree, or unequal, if the persons placed in each line are distant from the common stock by a diverse degree. Thus two brothers are of an equal line, but a brother and a brother's daughter are of an unequal line.

3. Degree is the measure of the distance of one person from another in the same line. Degree can be simple or mixed.

591. Principles.¹ 1. In the direct line of consanguinity, matrimony is invalid between all ascendants and descendants, both legitimate and natural.

Therefore consanguinity dirimently impedes matrimony in any degree, by positive law at least, probably also by natural law.

Authors who affirm that consanguinity dirimently impedes matrimony indefinitely by natural law use this argument: all descendants owe to progenitors almost the same reverence which children owe to parents; therefore progenitors are accustomed to be called by the name parents, descendants by the name children. For this reason, consanguineous persons in the direct line are not judged to have received from God the power of handing over to each other the right over their bodies.

But those who affirm that consanguinity by the positive law now in force dirimently impedes matrimony indefinitely teach that the supreme pontiffs (Callistus I and Nicholas I in the responses to the consultation of the Bulgars) received into ecclesiastical law the dispositions of Roman law invalidating matrimony between consanguineous persons in any degree whatever.

2. In the collateral line, matrimony is invalid up to the third degree inclusively, but not beyond, even if a more remote degree is mixed with a nearer one, e.g., the fourth with the second.

The impediment, which formerly extended up to the seventh degree, was restricted by the Fourth Lateran Council under Innocent III, and afterward by the Council of Trent,² to the fourth degree, because of the great difficulty of observing the prohibitions of so many degrees, and by the new Code to the third degree. Therefore the fourth degree of consanguinity and the fourth touching the third no longer dirimently impede matrimony.

3. Matrimony is never to be permitted if a doubt remains whether the parties are consanguineous in some degree of the direct line or in the first degree of the collateral line, because the doubt is either certainly or probably of divine law.

¹ Cn. 1076.

² Sess. 24, c. 4, De reform. matr.

592. Origin of the Impediment. 1. In the first degree of the direct line (between father and daughter, mother and son) the impediment is certainly of natural law; in other degrees of the direct line marriages likewise seem to be invalid by natural law (secondarily), although some authors say that they are valid but illicit.

The reason of the first: by the natural light of reason itself we understand that the use of matrimony between consanguineous persons in the first degree of the direct line is contrary to the singular reverence owed to parents. Therefore almost all peoples not depraved in morals detest nuptials in the first degree of the direct line as wicked.¹ Wherefore, because of the natural baseness which inheres in marriages of this sort, consanguineous persons in the first degree of the direct line are judged by natural law to lack the power of handing over to each other the right over their bodies.

The reason of the second: all descendants indeed owe reverence to their progenitors, yet in a more remote degree this need not be so great as in the first. Wherefore nuptials between consanguineous persons also of a more remote degree of the direct line are opposed to natural law; but this repugnance does not seem to be so great that nuptials of this sort must be said to be absolutely invalid by natural law, but only by secondary natural law.

2. In the first degree of the collateral line (between brother and sister) the impediment is of natural law;² in the other degrees of the collateral line it is certainly of merely ecclesiastical law.

a. Several authors, both ancient and recent, deny that matrimony between brother and sister is invalid by natural law. And rightly indeed, if this is understood of primary natural law: for that singular reverence owed to parents, because of which nature itself forbids matrimony between parents and children, is founded chiefly in this, that parents are the principle of children. But in the collateral line this chief reason does not have force. Therefore nature does not absolutely forbid matrimony between brothers and sisters as it does between parents and children.³ Wherefore at the beginning, because of the most grave necessity of propagating the human race, which God willed to descend from one man, marriages between the sons and daughters of Adam were valid by divine disposition; but afterward, when the human race had already been sufficiently propagated, they became invalid by natural law.

b. Therefore concerning marriages which consanguineous infidels enter within the degrees prohibited by the Church, these things must be held:

a. Marriages entered between consanguineous persons in the first degree of the direct line are certainly invalid. The same must be said of marriages of consanguineous persons which are invalidated by civil law.

b. Matrimony entered between grandfather and granddaughter, and matrimony entered between brother and sister, is likewise invalid. If spouses of this sort are converted to the faith, they can enter a new matrimony according to the practice observed by the Holy See. If doubt remains concerning the value of a matrimony contracted in infidelity, one must stand for the nullity of the matrimony in favor of the faith.⁴

c. Marriages of consanguineous persons in the second and further degree, if nothing else stands in the way, are valid; and if the spouses are converted to the faith, they can remain in the contracted matrimony without dispensation.

3. The reason for prohibiting marriages to be contracted between consanguineous persons is chiefly threefold: one social, that mutual charity and friendship may be extended more widely; another moral, that, once hope of matrimony has been taken away, carnal love among members of the family may be restrained; and finally another physical, that provision may be made for offspring. For it is established that marriages of consanguineous persons are either unfruitful or that offspring often suffer from diseases and defects.⁵

¹ The Assyrians and Persians are to be excepted, who did not reject marriages between a son and his own mother; the Egyptians permitted marriages between brother and sister.

² Council of Trent, sess. 24, c. 5, De reform. matr.

³ Gen. 20, 12.

⁴ S. Office, May 18, 1872.

⁵ Cf. Wernz IV, n. 413 ff.

593. Canonical Computation of Degrees.¹ For computing degrees of consanguinity in canon law, three rules are established: one for the direct line, another for the equal collateral line, another for the unequal collateral line.

1. In the direct line there are numbered as many degrees as there are persons, the stock being removed, or there are as many degrees as there are generations.

Descendants          Titius.          Ascendants

1                                      1
Son                                    Father

2                                      2
Grandson                               Grandfather

3                                      3
Great-grandson                         Great-grandfather

Therefore father and son are consanguineous in the first degree, grandfather and grandson in the second, great-grandfather and great-grandson in the third.

In the appended schema Titius is consanguineous in the direct line with his father and son in the first degree, with his grandfather and grandson in the second, and with his great-grandfather and great-grandson in the third.

2. In the equal collateral line there are numbered as many degrees as there are persons on one side, the stock being removed. Therefore two persons are consanguineous in that degree by which they are distant from the common stock.

                 Claudius.

1                         1
       Anna                     Titius

2                         2
     Iacobus                   Theresia

3                         3
      Maria                    Iulius

Therefore brother and sister are consanguineous in the first degree of the equal collateral line; the children of a brother and the children of a sister (paternal and maternal cousins) in the second; the grandchildren of a brother and the grandchildren of a sister in the third.

In the appended schema, Iulius and Maria are consanguineous in the third degree, Iacobus and Theresia in the second, Titius and Anna in the first degree of the equal collateral line.

3. In the unequal collateral line there are numbered as many degrees as there are persons on the more remote side, the stock being removed. Therefore two persons are consanguineous in that degree by which the more remote person is distant from the common stock.

                 Sempronius.

1                         1
      Flavia                    Lucius

2                         2
       Anna                     Petrus

3                         3
      Caesar                    Victor

4
                                Melania

If therefore on one side there are three persons, and on the other side four persons, the stock being removed, the last two persons are consanguineous in the fourth degree of the unequal collateral line. A mixed degree of this sort is customarily expressed in this way: A and B are consanguineous in the fourth degree mixed with the third, or also in the fourth degree touching the third.

In the appended schema Melania and Caesar are consanguineous in the fourth degree touching the third. Victor and Anna are in the third degree touching the second, Petrus and Flavia in the second degree touching the first of the unequal collateral line.

¹ Cn. 96.

594. Names of Consanguineous Persons. 1. Names of ascending consanguineous persons in the direct line on the part of the father and mother:

First degree: pater, Vater; mater, Mutter.

Second degree: avus, Grossvater; avia, Grossmutter.

Third degree: proavus, Urgrossvater; proavia, Urgrossmutter.

2. Names of descending consanguineous persons in the direct line on the part of the father and mother:

First degree: filius, Sohn; filia, Tochter.

Second degree: nepos, Enkel; neptis, Enkelin.

Third degree: pronepos, Urenkel; proneptis, Urenkelin.

3. Names of descending consanguineous persons in the collateral line on the part of the father:

First degree: frater, Bruder; soror, Schwester.

Second degree: patrueles, Geschwisterkinder, when the two fathers are brothers; amitini, Geschwisterkinder, when the father of one and the mother of the other are siblings.

Third degree: patrueles magni, amitini magni, other Geschwisterkinder.

4. Series of descending consanguineous persons in the collateral line on the part of the mother:

First degree: frater, Bruder; soror, Schwester.

Second degree: consobrini, Geschwisterkinder whose mothers are sisters.

Third degree: consobrini magni, other Geschwisterkinder.

5. Names of ascending consanguineous persons in the collateral line on the part of the father:

First degree: patruus, Onkel (father's brother); amita, Tante (father's sister).

Second degree: patruus magnus, Grossonkel (grandfather's brother); amita magna, Grosstante (grandfather's sister).

Third degree: propatruus, great-grandfather's brother; proamita, great-grandfather's sister.

6. Names of ascending consanguineous persons in the collateral line on the part of the mother:

First degree: avunculus, Oheim (mother's brother); matertera, Muhme (mother's sister).

Second degree: avunculus magnus, Grossoheim (grandmother's brother); matertera magna, Grossmuhme (grandmother's sister).

Third degree: proavunculus, great-grandmother's brother; promatertera, great-grandmother's sister.

595. On Multiple Consanguinity. From multiple consanguinity there arises a multiple impediment of consanguinity. Now consanguinity is multiple if two persons come together in several stocks.¹

        Aloisius              Stanislaus

Caius        Leo - Agnes        Bertha

Cornelius       Petrus  Anna       Maria

Cornelius, the betrothed man, and Anna, the betrothed woman, descend from a double stock (Aloisius and Stanislaus). Therefore they are consanguineous in the second equal degree both from the stock Aloisius and from the stock Stanislaus.

Double Diverse Stock.

                         Carolus

Petrus          Maria          Anna

Iacobus          Henricus

Felix           Lucia

Felix, the betrothed man, and Lucia, the betrothed woman, descend from a double stock (Petrus and Carolus). Therefore they are consanguineous in the second equal degree from the stock Petrus and in the third equal degree from the stock Carolus.

Two Causes in One and the Same Marriage.

                         Iulius

Pius                      Leo

Caia      Flavia   Titus        Paulus

Linus                 Anna

Linus, the betrothed man, and Anna, the betrothed woman, are consanguineous in a double second degree, because they descend from a double stock (Pius and Leo); moreover, in the third degree, because they descend from the common stock Iulius.

¹ Cn. 1076, 2: "The impediment is multiplied only as many times as the common stock is multiplied"; formerly it was multiplied also when two persons descended from the same stock by a multiple way.

596. Note 1. In order to detect whether, and what kind of, impediment of consanguinity exists between two betrothed persons, the more apt method, namely where the stock is unknown, seems to be this: that above the names of the betrothed man and woman there be written the names of father and mother, grandfather and grandmother, and so on up to the fourth generation. If among the ascendants of each, thus described, no common stock is found, no kinship intervenes between them; but if among the ascendants a common stock is found, the degree by which each is distant from it must be computed. Once this has been done, it will be established what kind of consanguinity exists between them.

Note 2. From what has been said it is clear that between the law hitherto in force and the new Code there is a twofold difference with regard to the impediment of consanguinity:

a. Hitherto consanguinity dirimently impeded matrimony in the direct line indefinitely in any degree whatever, in the collateral line up to the fourth degree; now it dirimently impedes matrimony in the direct line indefinitely, in the collateral line up to the third degree inclusively. Therefore consanguinity in the fourth degree and in the fourth degree touching the third no longer dirimently impedes matrimony.

b. Hitherto the impediment was multiplied both from plurality of stocks and from plurality of ways through which one could ascend to the stock; now it is multiplied from plurality of stocks only.

Consanguinity is the bond of relationship by blood existing between those who are descended by carnal generation from one and the same near stock. The relationship, therefore, arises from community of blood derived from a common and not too remote ancestor. That common ancestor is called the stock; the distance in descent between one person and the other is called the degree of relationship; and the series of persons who descend from the same stock is called the lie, which is direct if they descend from one another, otherwise it is collateral. The degrees are equal in the collateral line if the persons are equally distant from the common stock; otherwise they are unequal.

It is immaterial whether both parents of the common stock are the same or only one, and whether the birth be legitimate or not.

The method of computing the degrees differs somewhat in canon law from that adopted by modern English civil law, which here follows the Roman civil law. The following are the rules for reckoning the degree of relationship according to canon law, which is followed in moral theology:

(a) To find the degree of relationship in the direct line, count the persons, leaving out the common stock.

(b) In the collateral line, when the degrees are equal, count the persons in one of the lines of descent, leaving out the common stock.

(c) When the degrees are unequal, count the longer line, leaving out the common stock in the same way, and add the number of persons in the shorter line. Thus, an uncle and niece are related in the second degree, touching the first, or mixed with the first (Can. 96).

According to the English method of computation, which is also followed in most States of the Union, all the persons are counted both in the direct and collateral lines, leaving out the common stock. According to this method, an uncle and niece are in the third degree.

Consanguinity in the first degree of the direct line annuls marriage by the natural law; and in further degrees indefinitely, but more probably only by ecclesiastical law. In the collateral ‘ line it is disputed whether consanguinity in the first degree annuls marriage by the law of nature or not; it certainly does so to the third degree by ecclesiastical law.¹

This impediment, therefore, is partly of natural, partly of ecclesiastical law, and although in the more remote degrees of both the direct and collateral line it does not bind those who are not baptized, yet even among them there is a natural bond in blood relationship which after Baptism becomes a diriment impediment of marriage within the prohibited degrees. One who is baptized is subject to the laws of the Church, and cannot, without the necessary dispensation, marry a relation within the forbidden degrees, even if the latter is not baptized.

English law follows in this matter that of Leviticus, and according to its method of computation consanguinity is a diriment impediment of marriage to the third degree inclusive, but not beyond. Thus an uncle cannot marry a niece, but two cousins may marry, by English law.

¹ Council of Lat. 4 (1215); can. 1076.

The impediment of consanguinity may be multiple from various causes, but it is only multiplied as often as the common stock is multiplied (Can. 1076, sec. 2).

(a) If two near relations marry, their offspring will be related in several different ways: [diagram in the original]. In this scheme G and H are descended from the common stock C=F, and so they are in the second degree mixed with the first in the collateral line. Both G and H are also descended from A=B through C and through F. On this account they are in the third degree of relationship. Thus there is a double relationship between them, and if a dispensation were required for G to marry H, mention should be made of this fact.

(b) Similar results will follow if two relatives marry two relatives: [diagram in the original].

In this scheme G and H are descended from both A and B, and they are in double second degree of relationship.

(c) Similarly, if one man successively marries two who are related to each other: A D=B’ ‘C+D E F G H G and H are in the second degree from the common stock D, and in the third from the common to marry his deceased wife’s sister.

Affinity

800. Statements. - I. Consanguinity in the direct line, at least by positive law, invalidates matrimony indefinitely in any degree whatever. This is evident from Canon law in the Response of Nicholas I to the Bulgarians, chapter 37.

II. Consanguinity in the collateral line invalidates matrimony through the fourth degree inclusively, and not beyond. This is established from the Fourth Lateran Council and several places of Canon law.

III. Consanguinity invalidates matrimony also between those who were born only of the same father or only of the same mother; likewise between blood relatives born of illegitimate unions. The reason is that diversity of father or mother, or illegitimacy, does not prevent carnal consanguinity from existing between them.

801. • I. Rule. In the direct line, as many degrees are counted as there are persons, with the stock omitted; or there are as many degrees as there are generations. Hence between father and son there is one degree, because there is one generation, or one person of the son, with the father excluded as the stock. Between a grandson and grandfather two degrees are counted, because there are two generations, although three persons intervene, namely, the grandfather, the father, and his son, or the grandson with respect to the grandfather. Likewise posit a great-grandfather or great-great-grandfather, and you will have three or four degrees.

II. Rule. In an EQUAL collateral line, there are as many degrees as there are persons on one side, with the stock omitted. Hence a brother and sister are in the first degree, because if the common stock or father is set aside, one person remains on each side; and since each is distant by one degree from the stock, they also are distant from each other by one degree. Likewise paternal first cousins, or the children of two brothers, are each distant by two degrees from the common stock or grandfather, and therefore are blood relatives to each other in the second degree. The same must be said of others.

III. Rule. In an UNEQUAL collateral line, there are as many degrees as there are persons on the more remote side, always with the stock omitted. Hence if one is distant from the common stock by two degrees and his blood relative by three, they will be blood relatives to each other in the third degree, according to the saying: The more remote degree draws the nearer to itself. Therefore Berta will be related in the second degree to her paternal uncle, or her father's brother, because she is distant by two degrees from the common stock, namely, her grandfather, although the paternal uncle himself is separated by one degree from the same stock, since he is the son of the stock, or the brother of Berta's father. The same must be established concerning all others.

For computing degrees according to civil law, the number, or sum, of all the persons in each line is taken, with the stock omitted. Therefore in the direct line they are computed in the same manner as canonical degrees; in an equal collateral line, the canonical degrees are doubled; in an unequal collateral line, the lesser line is doubled and the excess of the greater is added.

802. Questions. - QUESTION 1. By what law does consanguinity in the aforesaid degrees invalidate matrimony?

Reply 1. It is certain that consanguinity in the direct line invalidates matrimony in the first degree by natural law and, more probably according to the opinion of certain Theologians ¹, indefinitely also in the other degrees. But the case, as is evident, is most remote from practice.

¹ Others, however, think differently; and omitting for now the various opinions - in Schmalzgrueber, book 4, title 14, no. 30 - which extend the force of this impediment to more or fewer degrees, there are those who, with St. Thomas, think that only the first degree renders nuptials invalid by natural law. St. Alphonsus (book 6, no. 470) holds this opinion equally probable with the one which the Author reports, and several others with Schmalzgrueber (ibid., no. 31) judge it preferable to the others. But, as the Author well observes, these things contribute nothing to practice.

Reply 2. As regards the collateral line, in the first degree it more probably ² invalidates by natural law, or at least by positive divine law, since the Church never dispenses so that brothers and sisters may be joined, and infidels themselves detest nuptials of this kind; in the other degrees, according to all, it invalidates by ecclesiastical law ³, as is deduced from the practice of the Church, which dispenses from them.

² The Doctors disagree whether matrimony between brother and sister is invalid by natural law, and some call the affirmative opinion more probable, others the negative. Some contend that the Roman Pontiffs never dispensed as regards this degree, others that they sometimes dispensed. See Schmalzgrueber, book 4, title 14, nos. 45-46. And, as St. Alphonsus also observes (book 6, no. 470), St. Thomas also stands for the opinion which judges this union valid by natural law. It would indeed be useless to review the arguments of each side and the replies to the contrary reasons, which can be seen everywhere among the Doctors. See St. Alphonsus, l.c., and Schmalzgrueber, l.c., nos. 45-48. Meanwhile observe how much prejudice spontaneously flows from this against the opinion which, while denying to princes the power of establishing diriment impediments for infidel subjects, contends that natural law alone has force for them. For if this is presupposed, a matrimony contracted in infidelity between a brother and sister could not be held certainly invalid, however much it might be condemned by their laws; and since in a doubt, according to the general principle, one must stand for the validity of the matrimony, if both of them were converted to the faith they consequently could not be separated, even if that union were a scandal at once to infidels and to the faithful.

³ Hence follows a consequence of the greatest importance. For since the laws of the Church do not bind those who are not baptized, marriages contracted between infidels who are joined in these degrees of consanguinity must therefore be held valid, considering natural law; and consequently, if they are converted to the faith, they are neither to be separated nor do they need a dispensation in order to remain in the union contracted. What is said concerning the impediment of consanguinity must also be said concerning the other impediments of merely ecclesiastical law.

The Doctors disagree whether marriages which heretics enter with an impediment of merely ecclesiastical law are to be held valid. See Schmalzgrueber, book 4, title 1, nos. 378-380, who, after bringing forward the reasons of each opinion, appears to incline toward the affirmative side.

QUESTION 2. How can degrees of consanguinity be found easily?

Reply 1. If the common stock is known, write that person's name on a sheet, and below it set down the generations and names of the persons descending on this side and that until you arrive at the persons to be joined in matrimony; from this you will easily compute the degrees.

Reply 2. If the stock is unknown, proceed thus: Write in the lower part of the sheet or table the name of the bridegroom on one side and the name of the bride on the other. Then above the name of the bridegroom note the names of those blood relatives who perhaps can be the cause why some relationship exists with the bride; do the same with respect to the bride. When this notation has been made, ascend on one side and see whether they meet in a common origin or stock from which the bridegroom and bride were mediately generated. Hence, after you have found it and at the same time observed whether the spouses are in an equal or unequal line, finally apply the rules to be proposed below, and the resolution of the doubt will be evident. Let the following be an example of these things:

Great-great-grandfather: Didacus Noel

In this example Petrus Pascal and Maria Noel are blood relatives in the equal fourth degree. But if Maria Noel descended immediately from Maurus Noel, Arthur Noel would be her grandfather and Didacus Noel her great-grandfather, and therefore they would be blood relatives in the fourth degree, but touching the third.

832. Divisions. Consanguinity is distinguished:

a) as legitimate and illegitimate, according as generation was effected in a valid or putative matrimony, or outside matrimony. Illegitimate offspring, however, can be legitimated, as will be said below, n. 884;

b) as full (perfect) and less full (imperfect), according as consanguineous persons descend from the same two parents, or only from the same father or the same mother. - Brothers having the same father but not the same mother are called "consanguineous"; but those having the same mother but not the same father are called "uterine"; while those having the same father and the same mother are called "germane";

c) as cognation and agnation, according as consanguinity arose through the female line or mother, or through the male line¹⁸⁴ or father;

d) as simple and multiple, according as two consanguineous persons descend from one common stock, or according as several common stocks are present. Thus according to the discipline now in force.¹⁸⁵ Formerly other cases of multiple consanguinity also occurred.

Since in practice it is sometimes sufficiently difficult to discover multiple consanguinity, it is necessary to explain at somewhat greater length at least two cases of multiple consanguinity.

¹⁸⁴ In the old German law, cognates were called Spillmagen and agnates Schwertmagen.

¹⁸⁵ Code of Canon Law, can. 1076, § 2.

836. Extent of the impediment of consanguinity. According to the discipline now in force in the Latin Church, consanguinity in the collateral line dirimes matrimony up to and including the third degree; and it makes no difference whether the consanguinity arose from a legitimate or an illegitimate bed.¹⁹¹

Formerly the impediment of consanguinity in the collateral line extended to the seventh degree and, after the Fourth Lateran Council, to the fourth degree; but now, after May 19, 1918, it is restricted to the third degree. - Since, according to the adage cited repeatedly, the more remote degree draws the nearer to itself, the diriment impediment of consanguinity is no longer present if on one side of the contracting parties there are four degrees up to the common stock, although on the other side there are only two or three degrees. - The best rule to be given to the people and sufficiently easy to apply in practice for discerning whether the impediment of consanguinity is present is this:

The impediment of consanguinity is not present if the parents of those about to marry were not at least first cousins, or, what is the same: if the grandparents of those about to marry were not brothers or sisters.

¹⁹¹ Code of Canon Law, can. 1076, § 2. In the Eastern Church this impediment is valid up to the seventh degree, that is, up to the third degree according to the canonical computation. Cf. Papp-Szilagyi, loc. cit., § 107.

S. Th., Suppl., q. 54, 56 and 57.

902. Kinship (parenté; verwantschap) is here understood as the propinquity or conjunction of persons, insofar as it is impeditive of matrimony; and, by reason of its cause or origin, it is distinguished as threefold: natural or carnal, - spiritual, - and legal, according as it arises from natural generation or filiation, from spiritual generation and filiation, or from legal filiation or adoption.

903. Carnal kinship or consanguinity (parenté naturelle, consanguinité; natuurlijke- of bloedverwantschap) is the propinquity or conjunction of persons, of whom one descends from another, or all descend from the same proximate stock through carnal generation. It is founded upon communion of blood, which through natural generation from carnal copula, licit or illicit, is derived from father and mother together, or from either one. Hence matrimony is equally prohibited among cognates and agnates, uterine, consanguine, and full kin.

So that consanguinity may be well understood, one must distinguish stock, line, and degree. A stock is a person from whom others descend. A line is an ordered series of persons descending from the same stock. A degree is the measure of the distance of one person from another in the same line of consanguinity.

One line is direct, which is constituted from persons of whom one descends from another, and it is subdivided into the line of descendants, who draw origin from others, and of ascendants, from whom others arise; another is transverse, oblique, or collateral, which is constituted from persons who descend from a common stock, without, however, one proceeding from another. This latter is equal or unequal, according as the collateral persons are distant from the common stock in an equal or a diverse degree.

For computing the degree of consanguinity, the following rules from can. 96 have force in canon law:

1° In the direct line there are as many degrees as there are generations; or as many persons composing the line, the stock being removed. Thus father and son are consanguineous in the first degree, grandfather and grandson in the second.

2° In an equal collateral line there are as many degrees as there are generations in one tract of the line, or as many persons in one series, the stock being removed. Thus brother and sister are in the first degree, first cousins in the second.

3° In an unequal collateral line there are as many degrees as there are generations in the longer tract of the line, or as many persons in the more remote series, the stock being removed. Thus an uncle with his niece is consanguineous in the second degree; by others it is said: in the second degree touching the first, or the second mixed with the first. An unequal or mixed degree, according to the style of the curia, is to be expressed in the petition for dispensation.

Let it be noted that in civil law the rule has force universally: there are as many degrees as there are generations. Hence in the direct line the computation is the same as in canon law; in the collateral line it is different, so that the degrees are computed from both sides and therefore are doubled in an equal line, and in an unequal line are added to one another.

904. Principle I. In the direct line of consanguinity, matrimony is void between all ascendants and descendants, both legitimate and natural, i.e., indefinitely. - Thus can. 1076, § 1.

The reason is the reverence and subjection owed to ascendants, with which the offices of spouses do not agree; whence the impediment is of the law of nature. St. Thomas shows this thus, q. 54, a. 3:

"1° That which human nature has in its first condition is of the law of nature. But from its first condition human nature had this, that father and mother were excluded from matrimony, which is clear from what is said, Gen. II, 24: For this cause a man shall leave father and mother; which cannot be understood with respect to cohabitation, and so it must be understood with respect to the conjunction of matrimony. Therefore consanguinity impedes matrimony according to the law of nature...

"2° In matrimony that is said to be against the law of nature by which matrimony is rendered unsuitable with respect to the end to which it is ordered. But the end of matrimony per se and first is the good of offspring. This indeed is impeded by some consanguinity, namely, between father and daughter or son and mother, not indeed so that it is totally taken away, because a daughter can receive offspring from the seed of her father and together with her father nourish and instruct it, in which the good of offspring consists; but so that it is not done in a fitting manner. For it is disordered that a daughter be joined to her father by matrimony as a companion, for the sake of generating and educating offspring, when she ought through all things to be subject to her father, as proceeding from him. And therefore it is of the law of nature that father and mother be repelled from matrimony. And even more mother than father; because more is derogated from the reverence which is owed to parents if a son takes his mother than if a father takes his daughter as wife, since a wife ought in some way to be subject to her husband."

905. Principle II. In the collateral line, matrimony is void up to the third degree inclusive, yet so that the impediment of matrimony is multiplied only as often as the common stock is multiplied. - Thus can. 1076, § 2.

A threefold reason for the impediment is indicated by St. Thomas, II-II, q. 154, a. 9: 1. the reverence owed to parents and consequently to other consanguineous persons who draw origin from the same parents, to which the baseness inherent in venereal commingling is contrary; - 2. the restraining of concupiscence among consanguineous persons who make use of familiar association; - 3. the extension of friendship with outsiders. Cf. q. 54, a. 3. To these can be added a reason from the physical order, because harm from these unions, by force of heredity, more easily arises for the offspring.

The impediment is of ecclesiastical law, except in the first degree: namely, matrimony between brother and sister seems rather to be against natural law, not indeed primary but secondary, and against divine law.

According to present-day discipline:

1° The impediment renders matrimony void up to the 3rd degree inclusive, but not beyond, even if the more remote degree is mixed with the nearer, e.g., the fourth with the second. Hence it can be said that matrimony cannot be entered between those whose grandparents are brothers or sisters, but can be if they are distant by a more remote degree; - or, in other words, that the impediment does not extend beyond the children of first cousins, and great-grandchildren.

Formerly it urged up to the 7th degree; afterward by the Fourth Lateran Council and by Trent, sess. 24, c. 4, it was reduced to the 4th, and by the new code of law to the 3rd degree. The reason is that, as St. Thomas explains, q. 54, a. 4, formerly consanguineous persons were accustomed to dwell more in one family; but now toward more remote consanguineous persons there is almost no bond of greater friendship than toward outsiders. Hence beyond this it is useless to prohibit degrees of consanguinity, and also dangerous, because, concupiscence prevailing, men do not sufficiently observe the numerous multitude of consanguineous persons.

2° The impediment is multiplied only as often as the common stock is multiplied. Namely, from multiplied consanguinity the impediment is multiplied as often, namely, as the persons communicate in the same blood because of the multiplication of a common stock, or as often as they descend from several stocks.

Before the new code of law, consanguinity was also multiplied from the fact that either or both of the spouses descended from the common stock by a multiple way; but now only from the fact that the common stock is multiplied. This can happen in a threefold way: a) if several men consanguineous to each other have generated offspring from women consanguineous to each other; b) if someone has successively generated offspring from several persons consanguineous to each other, successively taken; c) if someone has generated offspring from a person consanguineous to himself, and the common ascendants are already consanguineous to each other. Moreover, several causes of multiple consanguinity can occur together even in one case.

906. Observations. - 1. The impediment of consanguinity, even insofar as it is established from the law of nature, is not only impedient but diriment; this is necessary so that the law may efficaciously remove from these marriages and attain its end.

2. Hence in an impediment which certainly or probably is of natural or divine law, the Church cannot dispense; whence can. 1076, § 3: "Let matrimony never be permitted, if there is any doubt whether the parties are consanguineous in any degree of the direct line or in the first degree of the collateral line."

3. In other degrees the Church can dispense; and indeed in the third degree easily, less easily in the equal second degree, and with difficulty in the second touching the first. And according to can. 1052, a dispensation is valid, even if an error concerning the degree has crept into the petition or concession, provided the degree really existing is inferior, or even if the multiplicity of the impediment in an equal or inferior degree has been kept silent.

4. Unbelievers, while they contract among themselves, are subject to impediments of natural and divine law, but not to impediments of ecclesiastical law. Hence marriages entered between unbelievers consanguineous in the direct line or in the first degree of the collateral line are to be held as invalid; nevertheless in practice recourse must be had to the Holy See. Marriages entered with other consanguineous persons are valid, unless the civil prince has established the impediment; if the impediment is doubtful, one must conclude for the nullity of the matrimony, in favor of the faith.

5. So that consanguinity may more easily be detected where the stock is unknown, above the names of the spouses there should be written the names of their ascendants up to the third degree. But if names are found common to each spouse, the impediment is present, and then the degree by which each is distant from such a common name is to be computed; otherwise the impediment is not present. - If it is present, special attention must be given to the three ways in which it is multiplied. 1

1. Let it be permitted to set forth the three ways schematically:

a. Consanguineous men generating offspring from consanguineous women:

                 John                         Joseph
                  |                            |
          +-------+-------+            +-------+-------+
          |               |            |               |
       Albert          Raymond       Mary           Aloysia

   Albert + Mary -> Louis
   Raymond + Aloysia -> Eugenia

Between Louis and Eugenia there exists a double impediment in the 2nd degree of consanguinity, because they have a double common stock, namely, the parents both of their father and of their mother.

b. A man generating offspring successively from several consanguineous women:

                         John
                          |
            +-------------+-------------+
            |                           |
         Martha                     Margaret
            |                           |
            +----------- Leo -----------+
            |                           |
          Peter                       Paul
            |                           |
          Mary                       Joseph

Between Joseph and Mary there is present a double impediment of consanguinity, one in the 2nd, the other in the 3rd degree, because they have a double common stock, namely Leo, their grandfather, and John, their great-grandfather.

c. A man generating offspring from a consanguineous woman, or common ascendants already consanguineous:

                         John
                          |
             +------------+------------+
             |                         |
           Luke                      Paul
             |                         |
       +-----+-----+                   |
       |           |                   |
      Leo       Eugenia             Andrew
       |           |                   |
       |           +---------+---------+
       |                     |
    Joseph                 Mary

Between Joseph and Mary there is present a double impediment of consanguinity, one in the 2nd degree, from the common stock Luke, the other in the 3rd from the common stock John.

Natural kinship, or consanguinity, is the bond of persons descending from the same nearest stock through carnal generation, or the bond which arises from participation of the same blood within certain limits.

In consanguinity three things must be distinguished, namely: 1°. the stock, or the person from whom the others draw origin; 2°. the degree, or the measure of the distance of one person from another; 3°. the line, or series of persons descending from the same stock. But the line is twofold: one direct, and the other collateral or transverse. The former is the series of persons of whom some descend from others, either immediately, as children from parents, or mediately, as grandchildren from grandparents or from great-grandparents, etc. But the latter is the series of persons who, although they have a common stock, nevertheless do not descend one from another, as brothers, cousins, etc. Besides, this is equal or unequal according as blood-relatives are equally or not equally distant from the common stock.

I say 1°. § 1. In the direct line of consanguinity, marriage is invalid among all ascendants and descendants, both legitimate and natural (Can. 1076), at least by positive law. - I said at least by positive law, because although it is certain that Marriage in the first degree of the direct line is null by the law of nature itself, nevertheless it is disputed among theologians whether it is dirimently invalidated by the same law in other degrees. - Cf. S. Alphonsus, de Sacram. Paenit., n. 470. - Schmalzgrueber, lib. 4, tit. 14, n. 30.

I say 2°. § 2. In the collateral line it is invalid up to the third degree inclusive, yet in such a way that the impediment of marriage is multiplied only as often as the common stock is multiplied (Can. 1076). But concerning the law of this impediment it must be said that it is from a positive ecclesiastical statute, as is deduced from the practice of the Church, which dispenses from it, except in the first degree, concerning which it is disputed whether it dirimently invalidates by ecclesiastical or natural law, or at least by positive divine law, since the Church never dispenses so that brothers and sisters may be joined, and unbelievers themselves detest nuptials of this kind. - Cf. Schmalzgrueber, loc. cit., nn. 45 and 46. - Ballerini, notes (a) and (b), p. 786.

I say 3°. § 3. Marriage is never to be permitted if there is any doubt whether the parties are blood-relatives in some degree of the direct line or in the first degree of the collateral line (Can. 1076).

But that the diversity of the degree of consanguinity may be computed, attention must be given to the following rules:

§ 1. Consanguinity is computed by lines and degrees.

Rule I. § 2. In the direct line, there are as many degrees as generations, or as many persons, with the stock removed (Can. 96).

Hence between father and son there is one degree, because there is one generation or one person of the son, the father being excluded as the stock. Between grandson and grandfather two degrees are counted, because there are two generations, although three persons intervene, namely grandfather, father, and his son, or grandson with respect to the grandfather. Suppose likewise great-grandfather or great-great-grandfather, and you will have three or four degrees.

Rule II. § 3. In the oblique line, if each tract is equal, there are as many degrees as generations in one tract of the line (Can. 96).

In the equal collateral line there are as many degrees as there are persons on one side, with the stock removed. Hence brother and sister are in the first degree, because if the common stock or father is set aside, one person remains on each side; and since each is distant by one degree from the stock, they also are distant from each other by one degree. Likewise paternal cousins, or the children of two brothers, are each distant by two degrees from the common stock or from the grandfather, and consequently are blood-relatives between themselves in the second degree. Thus also it must be said concerning the others.

Rule III. § 3. If the two tracts are unequal, there are as many degrees as generations in the longer tract (Can. 96).

Hence if one is distant from the common stock by two degrees and his blood-relative by three, they will be blood-relatives between themselves in the third degree, according to the saying: The more remote degree draws the nearer to itself. Therefore Bertha will be a blood-relative in the second degree with her paternal uncle, or the brother of her father, because she is distant by two degrees from the common stock, namely from her grandfather, although the paternal uncle himself is separated from the same stock by one degree, since he is the son of the stock, or the brother of Bertha's father. Thus also must it be established concerning any others.

Notice that these rules regard computation according to ecclesiastical law. But if the civil laws of some State compute differently, attention must be given to them, but only for civil effects. Cf. Kenrick, n. 153.

Question 1. How can the degrees of consanguinity easily be found?

Resp. If the common stock is known, write his name on paper, and below mark the generations and the names of the persons descending from here and there, until you come to those persons who are to be joined in wedlock; from this you will easily compute the degrees. - But if the stock is unknown, proceed thus: write in the lower part of the paper or table the name of the bridegroom on one side, and the name of the bride on the other; then above the bridegroom's name mark the names of those blood-relatives of his who perhaps can be the cause why some kinship exists with the bride; do the same with respect to the bride. When this notation has been made, ascend on one side, and see whether they come together in a common principle or stock, from whom the bridegroom and bride have been mediately begotten. Hence after you have found it, and at the same time have observed whether the betrothed are in an equal or unequal line, finally apply the rules proposed below and the resolution of the doubt will be clear. For these things let the following example stand:

                         GREAT-GRANDFATHER

PATRITIUS MURPHY

GRANDMOTHER                         GRANDFATHER
              Anna Murphy                         Petrus Murphy
              Wife of Joseph Smith

FATHER                              FATHER
              Michael Smith                       Joannes Murphy

BRIDEGROOM                          BRIDE
              Robertus Smith                      Maria Murphy

In the example Robertus Smith and Maria Murphy are blood-relatives in the third equal degree.

Another method also exists for recognizing the degrees of kinship, namely the use of the tree of consanguinity or of the genealogical table which is had on the following page. Therefore, that the whole matter may be done practically, inspect the table, and see in what line and in what cells you find the persons concerning whose kinship inquiry is made, and attend by how many degrees they are distant from the common stock.

Consanguinity between the same persons can arise from a multiple head, and then there is a double or multiple propinquity or impediment to be opened in the petition of dispensation. But this can happen when two or more common stocks concur. Thus, for example, if wives who are themselves sisters or cousins between themselves were married by two brothers or cousins, the children received from each wedlock will be joined between themselves by a double bond of consanguinity. - Cf. Scavini, lib. 3, tract. 12, n. 1012.

Question 2. Who are collateral blood-relatives?

PATRUUS MAGNUS, or brother of the grandfather - grandfather's brother.

AMITA MAGNA, or sister of the grandfather - grandfather's sister.

PATRUUS, or brother of the father - father's brother, paternal uncle.

AMITA, or sister of the father - father's sister, paternal aunt.

PATRUELES, or children of brothers from the father's side - first cousins.

AVUNCULUS MAGNUS, or brother of the grandmother - grandmother's brother.

MATERTERA MAGNA, or sister of the grandmother - grandmother's sister.

                                      3
                              Great-grandfather
                              Great-grandmother

3            2             3
                 Great paternal     Grandfather    Great maternal
                 uncle/aunt         Grandmother    uncle/aunt

3          2            1            2           3
         Their children  Paternal     Father       Maternal    Their children
                         uncle/aunt   Mother       uncle/aunt

3        2          1           N           1          2        3
   Nephews   Paternal    Brother                 Sister    Cousins   Nephews
             cousins                                      maternal
             Amitini                                      Amitini

3        2                       1                    2        3
   Second    Brother's               Son/Daughter        Sister's  Second
   cousins   children                                    children  cousins

3                                2                             3
   Brother's                         Grandson                      Sister's
   grandchildren                     Granddaughter                 grandchildren

3
                              Great-grandson
                              Great-granddaughter

Notes

I. This table represents consanguineous persons up to the third degree in the direct and collateral line.

II. Persons who are joined by a tract are blood-relatives between themselves in the direct line, and with the rest in the collateral line.

III. Where the lines are joined, there the stock is had.

AVUNCULUS, or brother of the mother - mother's brother, maternal uncle.

MATERTERA, or sister of the mother - mother's sister, maternal aunt.

CONSOBRINI, or children of brothers from the mother's side - first cousins.

AMITINI, or children of brothers - first cousins.

SOBRINI, or their children - second cousins.

NEPOTES, or children of brothers - nephews - brother's or sister's children.

PRONEPOTES, or their children - second nephews - grand nephews.¹

¹ Cf. Addenda, p. 1117, n. 70.

Spiritual kinship is a certain propinquity which, by statute of the Church, arises from the administration and reception of Baptism among certain persons determined in canon law.

VIII. QUESTION V. What is consanguinity, and of how many kinds is it? ANSWER. It is a bond of persons descending from the same stock, contracted by carnal propagation. It is divided into lines and degrees. A line is an ordered collection of persons descending from the same stock. It is twofold: one direct, which is the collection of those of whom one descends from another, as a son from a father, a grandson from a son, and so on to infinity. This is regarded in two ways. One is of ascendants, by which ascent is made from the begotten to the begetters, as from a son to a father, from a father to a grandfather, and so forth. The other of descendants, by which descent is made from a father to a son, from a son to a grandson, and so forth. The second line is transverse, which is the collection of those who descend from the same stock, without one deriving his origin from another, as brothers, cousins, and so forth. This is considered under a twofold aspect. One is equal, as two brothers, who descend in the same degree from a single stock. The other is called unequal, as an uncle and a nephew, who stand unequally distant from the same stock. A degree is the greater or lesser distance of one person from another according to the line of consanguinity. The stock, lastly, is called that person from whom the other blood-relations draw their origin, as the father is the stock of sons, and a grandfather of grandsons.

IX. QUESTION VI. How many are the rules which are assigned by theologians and canonists for the computation of the degrees of consanguinity? ANSWER. Three. 1. In the direct line of ascendants and descendants there are as many degrees as there are persons, the stock being taken away. Hence father, son, grandson, great-grandson, great-great-grandson are five persons and four degrees: the son is in the first degree with the father, the grandson in the second, the great-grandson in the third, the great-great-grandson in the fourth; since there are as many degrees as there are generations. 2. The rule: In the collateral equal line persons are distant from one another by as many degrees as they are from the common stock. Thus two brothers are distant in the first degree from one another, because they are distant by one degree from the stock. The sons of two brothers are blood-relations in the second degree, because they are distant in the same from the stock. 3. The rule is: In the collateral unequal line persons are distant from one another by as many degrees as he is distant from the stock who is the more remote. Wherefore an uncle and a brother's son are unequally distant from the grandfather, in whom they are conjoined. For the former is in the first, since he is his son; but the latter is distant in the second degree. Therefore they are distant from one another in the second degree, because the more remote person is distant by two degrees from the stock.

X. In the direct line canon law and civil law agree in the computation of degrees. In the transverse or collateral line the civil law differs from the canon. For the civil law numbers the degrees by persons, and numbers as many degrees as there are persons, the stock being taken away. Thus two brothers are indeed distant by one degree from the common father, but they are distant from one another by two degrees, because there are two persons; the sons of two brothers are distant in the fourth degree, because there are four persons, the stock being taken away. On the contrary canon law numbers the degrees not by persons but by the distance from the stock. The reason of the canonical computation is that persons in the transverse order are not conjoined with one another save by reason of the stock from which they descend. Therefore they cannot be more or less distant from one another than they are distant from the stock from which they descend. Hence two brothers are distant from one another in the first degree, because both are conjoined in the first with the stock. If they be unequally distant from the stock, as an uncle and a brother's son, they are distant from one another by that degree by which he is distant from the stock who is the more remote, as has been said.

XI. In the first degree of the direct line there are no marriages by the law of nature, as the Fathers commonly teach. Theologians dispute whether in every degree of the direct line marriages are unlawful, and whether Adam, if he should now rise again, could marry some woman; but this disputation I judge futile. For it is enough that there are none up to the fourth degree. For in the fifth degree they are either dead, or are in an age so bowed down that it would be most absurd to wish to contract matrimony between them.

Caius, a young man, committed adultery with Bertha and with Julia while their husbands were absent. Afterwards, having reformed his morals, Caius married a most honorable woman; nevertheless, with paternal affection he always secretly cherished Mary, born of Bertha, and Titius, whom Julia bore to him. After some years, astonished, he noticed that Titius and Mary, now adults, were joined in the greatest familiarity with each other, and finally, stupefied, he heard their banns proclaimed in church, for they intended to enter marriage. After some days Caius disclosed to a confessor the secret that no one else knew and asked about his obligations. Hence it is asked:

1. What are banns, and what obligation do they induce of disclosing impediments to marriage?

2. By what law was the impediment of consanguinity introduced, and how are the degrees of consanguinity of those who derive their origin from the same father but different mothers computed?

3. What is to be said of the case?

The first question was answered above, p. 259.

2. To what law is the impediment of consanguinity due, and how are the degrees of consanguinity reckoned of those who have the same father but different mothers?

Consanguinity in the first degree of the direct line annuls marriage by natural law; in the other degrees of the direct line it annuls marriage, but more probably only by ecclesiastical law. It is disputed whether consanguinity in the first degree of the collateral line annuls marriage by natural or by ecclesiastical law; in more remote degrees of the collateral line up to the fourth inclusive it annuls marriage by ecclesiastical law.¹ It is immaterial whether both parents of the common stock are the same or only one.

1 Manual of Moral Theology, vol. ii, 299.

3. The case. The banns of Titius and Mary were proclaimed, they being the illegitimate children of Caius by different mothers, and so they were half-brother and halfsister. They were related therefore in the first degree of the collateral line of consanguinity, but Caius, their father, was the only person who knew of the relationship. He asked his confessor whether he was bound to do anything to stop the marriage. No, he is not bound to stop the marriage. The impediment is probably only of positive not natural law, the parties are in good faith and know nothing about it, he could not effectually intervene without betraying himself and the two women with whom he had sinned, to say nothing of the danger of spoiling the lives of the young couple.