The codes introduced in the preceding monograph, only covered the common types of relationship. The rest are so rare that it was thought that their omission would not detract from the system. However, to show that the system is flexible enough to cater for the more exotic types, the code has been extended to include most of the remainder.

Descriptions of relationship can cause confusion unless one is aware of who is the observer and who is the observed. Although a relationship is a two-way affair, we need to specify who is the first person singular in any relationship. As already explained, this is done by choosing a 'proband' or nominated person, who is usually oneself or the person on whose behalf the relationship is being investigated. In any genealogical research, everyone else is considered as secondary, so we are looking at the relationship of a secondary person to the proband. All the codes in the previous monograph and the following sections are worked out in this way.

However, sometimes the relationship between two people may be viewed from the point of view of a third person. We talk of a brother-sister or uncle-niece relationship. Although this is not the main purpose of the code, it can be adapted to cope with this situation by linking the symbols of the two relatives with a dash. e.g. B - Sr and U - Nf.

Finally, there is only one relationship, which has no generic title covering both sexes (such as sibs, parents, grandparents, children or cousins). That is the Uncle/Aunt - Nephew/Niece relationship, which is always a bit of a mouthful, but can be shortened by using the code as follows: U/A - Nm/Nf. This is one of the deficiencies of the English language; perhaps a word already exists in other languages, which could be borrowed to cover this general relationship. For details of the following obscure relationships, please refer to the descriptions in the previous monograph.

Non-reciprocal Intergeneration Doubles

These can easily be recognised and differentiated from conventional double cousin relationships because one or both sides of the double are across generations, whereas both sides of a conventional double cousin relationship are members of the same generation. Because of this there will be two codes for each double, depending on which member is the proband. e.g. D(HU) and D(HNm) for Double (Half Uncle - Half Nephew). With single removed relationships, this was coded in previous tables by using a +/ - device, i.e. First Cousin, Male, (Once removed) was coded as Cm +/ -1 to allow for the 'forward' and 'backward' orientations. However, for consistency, two distinct versions have been given for each removed relationship in tables 10 and 11, so that they are of the same format as the first two entries in each case.

Also, to distinguish between the two kinds of 'once removed' double relationships, only the double part of the code, following the D symbol, is enclosed by brackets. e.g.

Conventional Double (First Cousins) Once RemovedD(Cm) +/- 1
Intergeneration Double (First Cousins Once Removed)D(Cm +/- 1)

With the irregular forms, there are vast numbers of combinations. If great uncles and twice removed cousins are included, there will be 95 combinations; and if this is extended to first degree forms, there will be 203. For this reason , only 12 of the more common ones are included to show the method.

Table 10 Coding for Non-reciprocal Intergeneration Doubles (Regular)

1. Double (Half Uncle/Half Aunt)D(HU)D(HA)
  Double (Half Nephew/Half Niece)D(HNm)D(HNf)
2. Double (Half Great Uncle/Half Great Aunt)D(HGU)D(HGA)
  Double (Half Great Nephew/Half Great Niece)D(HGNm)D(HGNf)
3. Double (1st Cousin-1st Degree-Once Removed-Fwds)D[Cm(I) + 1]D[Cf (I) + 1]
  Double (1st Cousin-1st Degree-Once Removed-Bwds)D[Cm(I) - 1]D[Cf (I) - 1]
4. Double (1st Cousin-Once Removed-Forwards)D(Cm + 1)D(Cf + 1)
  Double (1st Cousin-Once Removed- Backwards)D(Cm - 1)D(Cf - 1)
5. Double (1st Cousin-1st Degree-Twice Removed-Fwds)D[Cm(I) + 2]D[Cf (I) + 2]
  Double (1st Cousin-1st Degree-Twice Removed-Bwds)D[Cm(I) - 2]D[Cf (I) - 2]
6. Double (1st Cousin-Twice Removed-Forwards)D(Cm + 2)D(Cf + 2)
  Double (1st Cousin-Twice Removed-Backwards)D(Cm - 2)D(Cf - 2)
7. Double (Half First Cousin-Once Removed-Fwds)D(HCm + 1)D(HCf + 1)
  Double (Half First Cousin-Once Removed-Bwds)D(HCm - 1)D(HCf - 1)
8. Double (Half First Cousin-Twice Removed-Fwds)D(HCm + 2)D(HCf + 2)
  Double (Half First Cousin-Twice Removed-Bwds)D(HCm - 2)D(HCf - 2)
9. Double (2nd Cousin-1st Degree-Once Removed-Fwds)D[2Cm(I) + 1]D[2Cf (I) + 1]
  Double (2nd Cousin-1st Degree-Once Removed-Bwds)D[2Cm(I) - 1]D[2Cf (I) - 1]
10. Double (2nd Cousin-Once Removed-Forwards)D(2Cm + 1)D(2Cf + 1)
  Double (2nd Cousin-Once Removed-Backwards)D(2Cm - 1)D(2Cf - 1)
11. Double (2nd Cousin-1st Degree-Twice Removed-Fwds)D[2Cm(I) + 2]D[2Cf (I) + 2]
  Double (2nd Cousin-1st Degree-Twice Removed-Bwds)D[2Cm(I) - 2]D[2Cf (I) - 2]
12. Double (2nd Cousin-Twice Removed-Forwards)D(2Cm + 2)D(2Cf + 2)
  Double (2nd Cousin-Twice Removed-Backwards) D(2Cm - 2) D(2Cf - 2)
13. Double (Half Second Cousin-Once Removed-Fwds)D(2HCm + 1)D(2HCf + 1)
  Double (Half Second Cousin-Once Removed-Bwds)D(2HCm - 1) D(2HCf - 1)
14. Double (Half Second Cousin-Twice Removed-Fwds)D(2HCm + 2)D(2HCf + 2)
  Double (Half Second Cousin-Twice Removed-Bwds)D(2HCm - 2)D(2HCf - 2)

Table 11 Coding for Non-Reciprocal Intergeneration Doubles (Irregular)

1. Half Uncle/Half Aunt and 1st Cousin D(HU/Cm)D(HA/Cf)
  Half Nephew/Half Niece and 1st Cousin D(HNm/Cm)D(HNf/Cf)
2. Half Uncle/Half Aunt and 1st Csn. Once Rmd. (B) D(HU/Cm - 1) D(HA/Cf - 1)
  Half Nephew/Half niece and 1st Csn. Once Rmd. (F) D(HNm/Cm + 1)D(HNf/Cf + 1)
3. 1st Cousin and Half 1st Cousin Once Removed (F) D(Cm/HCm + 1)D(Cf/HCf + 1)
  1st Cousin and Half 1st Cousin Once Removed (B) D(Cm/HCm - 1)D(Cf/HCf - 1)
4. Half 1st Cousin and 1st Cousin Once Removed (F) D(HCm/Cm + 1)D(HCf/Cf + 1)
  Half 1st Cousin and 1st Cousin Once Removed (B) D(HCm/Cm - 1)D(HCf/Cf - 1)
5. 1st Cousin Once Rmd. and Half 1st Csn. Once Rmd. (F) D(Cm + 1/HCm + 1)D(Cf + 1/HCf + 1)
  1st Cousin Once Rmd. and Half 1st Csn. Once Rmd. (B) D(Cm - 1 /HCm - 1) D(Cf - 1/ HCf - 1)
6. 1st Cousin Once Rmd. and 2nd Cousin Once Rmd. (F) D[(Cm + 1)/(2Cm + 1)] D[(Cf + 1) /(2Cf + 1)]
  1st Cousin Once Rmd. and 2nd Cousin Once Rmd. (B) D[(Cm - 1) /(2Cm - 1)] D[(Cf - 1) /(2Cf - 1)]
7. Half 1st Cousin Once Rmd. (F) and 2nd Cousin D[(HCm + 1) /2Cm)] D[(HCf + 1) /2Cf)]
  Half 1st Cousin Once Rmd. (B) and 2nd Cousin D[(HCm - 1) /2Cm)] D[(HCf - 1 )/2Cf)]
8. Half 1st Cousin and 2nd Cousin Once Rmd. (F) D(HCm/ 2Cm + 1) D(HCf / 2Cf + 1)
  Half 1st Cousin and 2nd Cousin Once Rmd. (B) D(HCm/ 2Cm - 1) D(HCf / 2Cf) - 1)
9. 1st Cousin and 2nd Cousin Once Removed (F) D(Cm/ 2Cm + 1) D(Cf / 2Cf + 1)
  1st Cousin and 2nd Cousin Once Removed (B) D(Cm/ 2Cm - 1) D(Cf / 2Cf - 1)
10. Half Sib and Half Uncle/Half Aunt D(HB/HU) D(HS/ HA)
  Half Sib and Half Nephew/Half Niece D(HB/HNm) D(HS/HNf)
11. Half Sib and 1st Cousin Once Removed (F) D(HB/Cm + 1) D(HS/Cf + 1)
  Half Sib and 1st Cousin Once Removed (B) D(HB/Cm - 1) D(HS/Cf - 1)
12. Half Sib and Half 1st Cousin Once Rmd. (F) D(HB/HCm + 1) D(HS/HCf + 1)
  Half Sib and Half 1st Cousins Once Rmd. (B) D(HB/HCm - 1) D(HS/HCf - 1)

The last three in this list are also enhanced half sibs (see table 12). (F) and (B) refer to the 'backward' or 'forward' orientations. With numbers 6 and 7, where the digits 1 and 2 lie on either side of a forward slash it is advisable to use additional brackets to avoid the code (Cm+1/2Cm+1) being misread as 'first cousin plus half first cousin once removed'; even though H would normally be the correct code for a half relationship

Enhanced Half Sibs

The codes for enhanced half sibs are easily recognisable because one of the elements in the double relationship will always be that of half sib. The strength of the enhanced half sib relationship is dependent on the relationship between the two spouses of the common parent. If that relationship is already a double one, then we have a multiple relationship. This can easily be encoded, however, in the same style as the rest, by using a hierarchy of brackets. e.g. If the common parent is a male, and his two partner's are double first cousins of each other, then the children of these two unions will be both half sibs and double second cousins and can be coded as follows:

Males Females
D[HB/D(2Cm)]  D[HS/D(2Cf)]

Using square brackets is also advisable when including first degree relationships. e.g. If the two wives of the common father are identical twin sisters, the codes for the enhanced half sibs will be:
Males   Females
D[HB/Cm(I)]   D[HS/Cf (I)]

The codes for enhanced half sibs are in table 12.

Table 12 Coding for Enhanced Half Sib Doubles (All Irregular)

Relationship between
the two spouses of the
common parent
 Double Relationships Males Females
1. Identical Twins  [Half Sib and 1st Cousin (1st Deg.)] D[HB/Cm(I)] D[HS/Cf (I)]
2. Full Sibs  (Half Sib and 1st Cousin) D(HB/Cm) D(HS/Cf)
3. Half Sibs  (Half Sib and Half 1st Cousin) D(HB/HCm) D(HS/HCf)
4. Single 1st Cousins  (Half Sib and 2nd Cousin) D(HB/2Cm) D(HS/2Cf)
5. Half 1st Cousins  (Half Sib and Half 2nd Cousin) D(HB/2HCm) D(HS/2HCf)
6. 2nd Cousins  (Half Sib and 3rd Cousin) D(HB/3Cm) D(HS/3Cf)
7. Half 2nd Cousins  (Half Sib and Half 3rd Cousin) D(HB/3HCm) D(HS/3HCf)
8. Double 1st Csns  (Half Sib and Double 2nd Cousin) D[HB/D(2Cm)] D[HS/D(2Cf)]
9. Dble Half 1st Csns  (Half Sib and Dble Half 2nd Cousin) D[HB/D(2HCm)] D[HS/D(2HCf)]
10. Dble 2nd Cousins  (Half Sib and Dble 3rd Cousin) D[HB/D(3Cm)] D[HS/D(3Cf)]
11. Parent-Child -   (½ Sib and ½ Uncle/ ½ Aunt) D(HB/HU) D(HS/HA)
  (½ Sib and ½ Nephew/ ½ Niece) D(HB/HNm) D(HS/HNf)
12. Uncle/Aunt-Nephew/Niece -   ½ Sib and 1st Csn. Once Rmd. (F) D(HB/Cm + 1) D(HS/Cf + 1)
  ½ Sib and 1st Csn. Once Rmd. (B) D(HB/Cm - 1) D(HS/Cf - 1)
13. ½ Uncle/ ½ Aunt - ½ Nephew/ ½ Niece-  ½ Sib and Half 1st Csn. Once Rmd. (F) D(HB/HCm + 1) D(HS/HCf + 1)
  ½ Sib and Half 1st Csn. Once Rmd. (B) D(HB/HCm - 1) D(HS/HCf - 1)

Double Relationships from Reciprocal Cross-generation Marriages

Because the generations are deliberately cross-matched between the two sides of the family it makes coding difficult. The problem is that both individuals have the same reciprocal relationships to each other. There are two elements; i.e. A is both the half uncle and the half nephew to B, and B is both half uncle and half nephew to A. Also, A can be first cousin once removed from B, (both + and -) and B can be first cousin once removed from A, (both + and -).

Although this category can be regarded as containing both regular and irregular forms, the regular version is unusual in requiring two different (reciprocally opposite) relationships in the code, instead of only one. Furthermore, in the irregular group, the two different elements are also oriented in opposite directions, i.e. forwards and backwards through the generations, instead of in the same direction. In spite of the fact that these situations are rare and the need for abbreviation is limited, the following codes (table 13) are provided for completeness:

Table 13 Coding for Reciprocal Cross - generation Double Relatives

Parents   Codes
Regular Doubles   MalesFemales
Father/Daughter - Daughter/Father  
Father/Son - Daughter/Mother -  D(HU/HNm) D(HA/HNf)
Mother/Son - Son/Mother  
Uncle/Niece - Niece/Uncle  
Uncle/Nephew - Niece/Aunt -  D(Cm+1/Cm-1) D(Cf+1/Cf-1)
Aunt/Nephew - Nephew/Aunt  
½ Uncle/½ Niece - ½ Niece/½ Uncle  
½ Uncle/½ Nephew - ½ Niece/½ Aunt -  D(HCm+1/HCm-1) D(HCf+1/HCf-1)
½ Aunt/½ Nephew - ½ Nephew/½ Aunt  
Irregular Doubles     
Father/Daughter - Uncle/Niece  
Father/Son - Niece/Aunt    D(HNm/Cm-1) D(HNf/Cf-1)
Mother/Daughter - Nephew/Uncle   D(HU/Cm+1)D(HA/Cf+1)
Mother/Son - Nephew/Aunt  
Father/Daughter - ½ Niece/½ Uncle  
Father/Son - ½ Niece/ ½Aunt    D(HNm/HCm-1) D(HNf/HCf-1)
Mother/Daughter - ½ Nephew/½ Uncle   D(HU/HCm+1)D(HA/HCf+1)
Mother/Son - ½ Nephew/½ Aunt  
Uncle/Niece - ½ Niece/½ Uncle  
Uncle/Nephew - ½ Niece/ ½Aunt    D(Cm+1/HCm-1) D(Cf+1/HCf-1)
Aunt/Niece - ½ Nephew/½ Uncle   D(Cm-1/HCm+1)D(Cf-1/HCf+1)
Aunt/Nephew - ½ Nephew/½ Aunt  

Multiple Cousins and Multiple Births

For regular conventional multiple cousins and half cousins a prefix can be used as for regular double cousins.

Double first cousins: DCm, DCf, DHCm, DHCf.

Quadruple second cousins: Q2Cm, Q2Cf, Q2HCm, Q2HCf.

Octuple third cousins: O3Cm, O3Cf, O3HCm, O3HCf.

This can also apply to multiple half cousins based on half sib chains. (See monograph).

Triple half first cousins: THCm, THCf.

Quadruple half first cousins: QHCm, QHCf.

Octuple half second cousins: O2HCm, O2HCf.

The same prefixes can be used for irregular multiple cousins. e.g. Q(HCm+1/Cm/2Cm/2Cm+1). For very complicated ones the codes may be simplified by omitting the prefixes entirely. (See here ).

Identical (monozygotic) multiple births require similar codes to those for identical twins:

Twin Triplet Quadruplet Quintuplet Sextuplet Septuplet

B(IT) S(IT) B(ITr) S(ITr) B(IQ) S(IQ) B(IQn) S(IQn) B(ISx) S(ISx) B(ISp) S(ISp)

Finally, for fraternal multiple births, replace the I for identical with F in each case. e.g.

Fraternal triplet (full sib) : B(FTr) S(FTr) Fraternal triplet (half sib) : HB(FTr) HS(FTr).

Double (and Multiple) Relationships Caused by Inbreeding

Direct relationships can only be double when inbreeding takes place. The closer the inbreeding, the more bizarre are the relationships. Complex multiple collateral relationships are difficult to encode. It is probably best in complicated situations, to avoid ambiguities by omitting the prefix stating whether it is triple, quadruple etc., and simply place a forward slash between the separate elements. e.g.

HB/DCm/Cm, [D(Cf)+1]/2Cf /3Cf, D(Cm+1)/2Cm/3Cm. The following, (Table 14) is a selection of some of the most likely to be encountered, resulting from both legal and illegal inbreeding:

Table 14 Coding for Double (and Multiple) Relationships Caused by Inbreeding (Reg. and Irreg.)

Direct Relationships (Regular)(See here, here, and here) MALES FEMALES
Double Grandfather-Grandmother DGF DGM
Double Great-grandfather-Great-grandmother D2GF D2GM
Double Great-great-grandfather - Great-great-grandmother D3GF D3GM
Double Grandson-Granddaughter DGS DGD
Double Great-grandson - Great-granddaughter D2GS D2GD
Double Great-great-grandson - Great-great-granddaughter D3GS D3GD
Direct Relationships (Irregular) (See here and here)
Father - Mother/Grandfather - Grandmother D(F/GF) D(M/GM)
Grandfather - Grandmother/Grt-grandfather - Grt-grandmother D(GF/2GF) D(GM/2GM)
Son - Daughter/Grandson - Granddaughter D(Sn/GS) D(Dr/GD)
Grandson - Granddaughter/Grt-grandson - Grt-granddaughter D(GS/2GS) D(GD/2GD)
Multiple Collateral Relationships (Regular and Irregular) *
Full Sibs/Double first cousins (REF) (See here) B/DCm Sr/DCf
Full Sibs/Double second cousins (RLI) (See here) B/D2Cm Sr/D2Cf
Full Sibs/Double (First Cousins Once Removed) (RGH) (See here) B/D(Cm-1) Sr/D(Cf+1)
Combined Relationships (Irregular) (See here, here, and here)
Grandfather - Grandmother/Great Uncle - Great Aunt D(GF/GU) D(GM/GA)
Grandfather - Grandmother/Uncle - Aunt D(GF/U) D(GM/A)
Father - Mother/Uncle - Aunt D(F/U) D(M/A)
Father - Mother/Single First Cousins D(F/Cm) D(M/Cf)
Father - Mother/Half Sibs D(F/HB) D(M/HS)