MyCinnamonToastTM Parenting & Genealogy

Family Relationships--Consanguinity and Cousins

by Edna Katherine French

And so do his sisters, and his cousins, and his aunts!
His sisters and his cousins,
Whom he reckons up by dozens,
And his aunts!

—William Schwenck Gilbert (1836-1911)


Consanguinity? "Come on, Edna," I can hear you groaning. "I thought you used clear, understandable English, not jaw-breakers like that. What is that word and why do I have to know about it?"

OK, I promise I'll use it only one more time. Consanguinity is the blood relationship that exists among individuals that descend from a common ancestor. So everyone descending from great-great-however-many great grandpappy from the old country is related by the big word. In other words, you're related by blood, not adoption or marriage.

There are three subcategories of the big word--lineal, collateral, and half.

Those of you who read fantasy novels may have heard of the seventh son of the seventh son, with no mention made of other brothers or sisters. In genealogy, that kind of descendency is called lineal. Lineal relationships include a straight line between you, your parents, grandparents, great-grandparents, children, grandchildren, etc. Yup, that's the picture--lineal relationships are only for direct, straight-line descendency.

Well, what about sisters and brothers? They're in the second kind of family relationship--collateral. Collateral relationships include not only brothers and sisters, but also cousins, aunts, uncles, nieces, nephews, full cousins, first cousins, second cousins, and third cousins. Got all that, Bro...? Well, collateral relationships also include first cousins once removed, third cousins twice removed--shall I pause here? I personally feel like part of a Gilbert and Sullivan opera when I get to this point.

Fortunately, the third kind of family relationship is much easier to deal with. "Half" relationships exist when an individual is one of the family, descends from a common ancestor, but from a different spouse of the ancestor.

Just for information purposes, step and in-law relationships are not blood (oops, I almost used the big word again) relationships. They occur as a result of marriage.


Getting cousins straight is one of the most challenging aspects of family relationships in genealogy. This is especially true when we start working with full cousins and "removed"cousins. First cousins share the same grandparents. Second cousins share the same great-grandparents, etc. Full cousins are those that: 1) descend from a common ancestor; and 2) share the same number of generations as the person you are working with, whether it is yourself or another family member. "Removed" cousins are those that: 1) descend from a common ancestor; but 2)differ in the number of generations as the person you are working with, yourself or another family member. Let's look at some examples. You can refer to one of the charts listed in the Related Web Pages for help in understanding this table.

Your aunt's son

Your full, first cousin (same generation)

Your grandfather's son's son (not your brother)

Another full, first cousin (same generation as you are)

Your mother's first cousin's daughter

Second cousin

Your second cousin's son

Second cousin once removed

Your uncle's granddaughter

First cousin once removed


Why, Edna, are we spending so much time on this?

The answer lies in the frontispieces of your treasured family books with barely legible writing in pale brown ink fading more each year. It says things like, "Given to my best friend and Second Cousin from Katherine on occasion of her graduation, June 1894".

It wafts through the diaries and journals of your ancestors like the hums and clicks of a farming community party line as they talk about their relatives. "Did you hear that Pattie had her baby last night? Yep, seven pounds, it was. She's my second cousin once removed on my mother's side, you know. Ah, the party line and family line was great. After all, they well knew who Cousin Pattie was and who she was related to, but do you?

It tears at your heartstrings as you read Cousin Kate's love letters packed carefully in tissue paper, tied with ribbon and a dried bouquet. Wait! The card says, "To Kate. It can never be, because we are first cousins. With deepest love for eternity. Roland"

It waits at the next reunion when another female that looks sort of like you piles a heap of potato salad on her plate and says, "Are you directly related to Grandgranny Boyington?"

You squint against the sun and analyze her features--round snub nose, curly auburn hair--but the mouth is wrong. "No", you answer with a grin, pulling your insert the big word here chart out of your pocket. "But we could be what they call kissin' cousins. Let's see if we can figure it out."

Do we need to look further for reasons to learn more about the big word and family relationships? I think not. We just need to dig into this task with the grit and zeal that genealogists are known for, so that it can become another useful tool in our genealogical field kit. Best of luck to you!

Related Books and Products

Dozens of Cousins; Blue Genes, Horse Thieves, and Other Relative Surprises in Your Family Tree

by Lois Horowitz

I found a book that intrigued me and I give it to you just for fun--no promises about the contents. I haven't read it yet. If you have, please let me know what you think about it. I hope that you'll find it interesting.

Forbidden Relatives : The American Myth of Cousin Marriage

by Martin Ottenheimer

According to reviewers, this book was helpful and caused them to think about the historical and religious perspectives about cousin marriages.

Kinship: It's All Relative

by Jackie Smith Arnold

We pursue it as a hobby and search for it in the most out-of-the-way places . . . yet few of us actually know very much about kinship. For instance, do you know the degree of blood relationship, or consanguinity, between yourself and your first cousins? Between third cousins and second cousins once removed? Do you know anything at all about the removes? Do you understand the difference between a great-aunt and a grandaunt? And what about double first cousins? If you're a little vague about any of this, then this book is for you. In clear, practical terms it explains everything there is to know about kinship; about agnate and cognate kinship, collateral and fictive kinship, the kinship connection of orphans, foundlings, foster children, and adopted children. Everything! The expanded second edition features new chapters on the subjects of marriage, names, and wills (kinship and the rights of inheritance); an expanded treatment of other subjects, such as degrees of consanguinity and how to calculate blood relationships; and a new glossary, bibliography, and an index. this new second Jackie Arnold's acclaimed Kinship: It's All Relative is now more authoritative than ever.

Black Sheep and Kissing Cousins : How Our Family Stories Shape Us

by Elizabeth Stone

Elizabeth Stone interviewed more than 100 people of all ages and ethnic backgrounds and asked them to recount stories from their own family histories. She found that these stories not only impart a sense of belonging and of shared history, but also help us to define ourselves.

Related Web Pages

The Kinship Chart is a chart showing family relationships written in a grid format. In using this chart, place the person of interest in the upper left corner. Then the parents, grandparents, etc. of that person are shown both across the top row and down the left column. The children and full cousins are shown on the diagonal. This is a very easy chart to use to determine the family relationship between two persons who meet at a reunion, for example, so carry one with you when you go.

The chart takes a different approach and provides quite a clear explanation of how to use the relationship chart. The top left corner is the common ancestor, while the top row and left column list child, grandchild, great-grandchild, etc. The full cousins show along the main diagonal and the "removed" cousins in the rest of the chart.

This page shows the relationship of cousins. It is a simple, graphical chart that explains the concept of the relationships between generations of cousins. It also provides a short list of links with information about marriage between cousins.

This provides the legal definition of consanguinity, collateral, and lineal relationships. It does not discuss half relationships.

Several different systems of counting degrees of bilateral kinship relatedness have been proposed and employed by jurists, geneticists, and anthropologists. Frequently circles of kinship are defined in terms of the ambiguous measure of "cousin range". More precise systems include: 1)Civil Degree; 2)Canon Degree; and 3)Collateral Degree. This article also discusses group dynamics, networks, and social functioning of families and individuals within the families. brings you a fine article with good descriptions and clear definitions of the terms you have been reading about. If the charts have been confusing, copy this article and carry it with you to the reunion. Guaranteed to keep smiles on your faces as you work your way around the picnic table.

Can you marry your cousin? Here's an interesting site with information and resources for cousins who are romantically involved.

Search for your surname: