Is my first cousin’s child my first cousin once removed, or my second cousin. My mother is insisting on the latter, but I think it’s the former. Which one of us is right?
You’re right. Your child will be the second cousin.
The child of your first cousin is your first cousin once removed.
The number removed refers to the number of generations of separation.
Seconded! 
Your child and your cousin’s child are 2nd cousins.
3rd…Iggy
Yes, manson.
All straight cousins (no removal) have a common predecessor. They are in the same (horizontal on the chart) lineage line. You and your 1st cousins have the same grandfather. You and your 2nd cousins have the same great-grandfather. You and your 3rd cousins have the same G-G-grandfather.
Your cousin’s child is not this case. He is not on the same lineage line. He is your first cousin once removed. His child will be your 1st cousin twice removed.
The way I summarize it: count the number of “greats” in your common predecessor. Add 1, that is your degree of cousinry.
Common grandfather (0 greats + 1 = 1) first cousin
Common great-grandfather (1 great + 1 = 2) second cousin
Common g-g-g-g-g-grandfather (5 greats + 1 = 6) 6th cousin
Dennis
There’s genealogy software that you can buy, or try out, or check out online. They would call the child of your first cousin your first cousin, once removed. I used such freeware a decade ago, and was really excited to have it define these topics for me. It even predicted birth dates for barely known ancestors. Now of course, Ancestry dot com probably does way more.
Does “predecessor” have some meaning different from “ancestor”, because your cousin’s child has the same ancestor that your cousin and you share-- your common grandparents, who are also the cousin’s child’s great-grand parents.
Yeah, but they don’t share the same grandparent. The OP’s grandparent is the cousin’s child’s great-grandparent. I don’t know if that’s what mixdenny meant by “predecessor” though.
Is “once removed” defined to be in a certain direction? Is my mom’s cousin my second cousin once removed, because her kids are my second cousins, and she’s one generation removed? Or is she still my first cousin once removed, because she’s my mom’s cousin?
This.
Based on the “standard” terminology, you are.
However, your mother is not alone in thinking the way she does; I know a number of people, including both of my parents and a Ph.D., who would agree with your mother.
You should ask your mother, “If I had a child, how would he/she be related to my first cousin’s child?”
OP, your cousin’s child is your first cousin once removed. Your child and your cousin’s child are second cousins.
X removed goes both ways. Your mom’s first cousin is your first cousin once removed, and you’re her first cousin once removed.
I’m on my phone so I’ll leave the googling to you, but take a look at a Table of Consanguinity.
Here is wiki’s table of consanguinity. Note this is not your standard ancestral chart. All the labels are for the “Person” box in the upper left.
A piece of trivia: In Lord of the Rings, Aragorn and Arwen shared Eärendil and Elwing as ancestors. Since Arwen was the daughter of Elrond and Aragorn descended from his brother Elros, that makes them first cousins. The fact there’s about 65 removals makes their marriage less icky.
Your first cousin’s child is your first cousin once removed. Your first cousin’s child is your child’s second cousin.
I’ve worked on genealogy for years, and I am absolutely positive about this.
To determine degree of cousinship, I basically use mixdenny’s method of determining the distance to the closest shared direct ancestor.
Except I count grands (always 1) + greats, for the same result.
If the numbers are not the same for both cousins, subtract the smaller from the larger to get the removal factor.
Examples:
-
You and your first cousin share grandparents (thus first cousins).
-
You and your first cousin’s child share an ancestor who is your grandparent (distance = 1) and the child’s great-grandparent (distance = 2). The degree of cousinship is the smaller number, and the removal factor is 2-1. You are first cousins once removed.
-
Your first cousin’s grandchild is your first cousin twice removed.
-
Your first cousin’s grandchild and your child are second cousins once removed.
-
Your first cousin’s grandchild and your grandchild are third cousins.
Indo-European languages are very inferior for this sort of thing. I wonder why?
Other languages have more words for this sort of thing.
e.g.
- Aunt (Mother’s sister) or Aunt (Father’s sister)
- Sister-in-law (Wife’s sister) or Sister-in-law (Brother’s wife)
- girl cousin or boy cousin
etc.
Yes. The more sensible ones also clearly denote your peer generation [you, siblings, cousins, age cohort], the generation descending [children, niece and nephew - who themselves become a peer generation], and the generation ascending [parents, aunts and uncles].
Modern Australian indigenous usage reflects that with Cuz used for peers and Uncle / Aunty for ascending unless a more specific term applies.
Well, Hindi (and related languages) is pretty good at this, and is most definitely Indo-European.