Removed cousinships probably cause more misunderstanding than any other relationship. Although the subject is well covered in the main text, a further look would seem appropriate to identify any potentially difficult areas.

By definition, all relationships are a two-way affair and removed cousins are no exception. To rationalise their relationship, one of the two cousins should be regarded as the primary focus of attention and referred to as the nominee or proband. The other cousin being considered as dependant or secondary. The general term "cousins once removed", does not indicate who is the nominee, so it is not possible to determine which cousin is the senior one in terms of generations. My proposal to resolve this difficulty is to use the terms, "removed forwards" or "removed backwards" to identify the senior partner. e.g.

Figure 1 Four generation Pedigree

In the above diagram, if G is chosen as the proband; then J's relationship to G (i.e. looking at the relationship from G's point of view) is:

First cousin, female, once removed (forwards).

But if J is the proband, then G's relationship to J is:

First cousin, male, once removed (backwards).

I think one of the major causes of confusion is when the "forwards and backwards" terminology is applied, quite correctly, to a single nominated individual, as opposed to using it reciprocally in a mutual relationship between the same two individuals, as shown between G and J above.

Figure 2 Five Generation Pedigree

In the second diagram (Figure 2) Where K is the only nominated person, N's relationship to K is:

Second cousin, male, once removed (forwards).

But, I's relationship to K is:

First cousin, female, once removed (backwards).

Thus, the level of cousin relationship is different depending on whether you are looking forwards or backwards through the generations from the same person. Furthermore, the ability to look both ways, from the same nominee, is not always possible. e.g. Returning to Figure 1; if the nominated person is G, as before, then J's relationship to G will remain:

First cousin, female, once removed (forwards).

However, when looking back to E from G, E is not G's removed cousin, he is his Uncle.

There is no backward removed cousin relationship between E and G because D and E are full sibs, not cousins. Similarly, in Figure 2, E's relationship to the proband K is Great Uncle.

The fundamental rule for determining the level of cousin relationship when looking backwards or forwards in a "removed" situation is as follows: There are three relevant individuals in each removed relationship, two are contemporary cousins and the third, who is always positioned in a later generation, is the child, grandchild or other descendant of one of the two cousins. e.g. In Figure 2, where K is the same proband in two different relationships, when looking backwards:

H and I are the two cousins (first) and K is the third member.

But, when looking forwards:

K and L are the two cousins (second) and N is the third member.

Therefore, it is the relationship between the two contemporary cousins in each case, which determines the title, and the third person must be located at least a generation later than the two cousins.

A common error is to select the third person from an earlier generation. e.g. In Figure 2, when considering the relationship between K and I, the mistake is to choose K and L as the cousins (instead of H and I) and I as the third person (instead of K), which would, incorrectly, give the relationship as: Second cousins once removed instead of the true title of: First cousins once removed.

The direction, forwards or backwards, simply depends on who is the proband; the relevant cousin or the third person. The relevant cousin being the one who is not the parent or grandparent of the third member.

First cousins once removed are sometimes referred to as 1½ cousins and second cousins once removed as 2½ cousins. However, this terminology is not very satisfactory as it breaks down when applied to cousins two or three times removed, and should be avoided.

Finally, the number of times removed, i.e. once, twice or three times, depends on how many generations separate the two individuals. e.g. See Figure 3 and Table 5. In Table 5, the probands are printed in red. Also included are the codes introduced earlier here and the degrees of relationship.

Figure 3 Six Generation Pedigree

Table 5 Removed Cousins and Other Intergeneration Collateral Relatives

RelativesTitle of Relationship Code R
H - M First cousin, male, once removed (forwards) Cm + 1 1/16
L - P Second cousin, female, once removed (forwards) 2Cf + 1 1/64
R - O Third cousin, male, once removed (backwards) 3Cm - 1 1/256
O - I First cousin, female, twice removed (backwards) Cf - 2 1/32
L - R Second cousin, male, twice removed (forwards) 2Cm + 2 1/128
H - R First cousin, male, thrice removed (forwards) Cm + 3 1/64
I - D Uncle U 1/4
E - L Great niece GNf 1/8
O - E Great-great aunt 2GA 1/16
D - R Great-great-great nephew 3GNm 1/32

Difficulties with the nomenclature of removed cousins and the confusion between uncles/nieces etc. and removed cousins is understandable and stems from the complex nature of the relationships. However, using the definitions on here and the chart (Table 9) in the foregoing monograph, together with these notes, should prevent any further misunderstanding.