What is My Cousin’s Cousin to Me?

Marc McDermott
Last updated: December 4, 2023

Genealogy starts to get confusing when you introduce second and a half cousins, but what about your cousin’s cousin? 

This can be tricky to get your head around, which leads many people to ask what is my cousin’s cousin to me? 

Well, a lot depends on how you label this person, and how they are your cousin. If the cousin is the child of your uncle or aunt, related to your parents, then this person would also be your cousin. However, if this cousin is the child of a sibling to the parent of your cousin, but married into the family and not related by blood, then this person is not a relation. 

It all starts to get confusing, which is why we are going to shed some light on your cousins’ cousins in the following article. 

What exactly is my cousin’s cousin to me?

We’ve already established how this person can and cannot be related to you, but there’s more. If this cousin is the child of an unrelated parent, and this unrelated parent is related to your parent, then you could be related to your cousin’s cousin.

If you and your cousin are all from the same set of siblings as each other’s first cousins, and all your parents are siblings of one another, then your cousin’s cousin is also your cousin. 

Is a cousin’s cousin blood-related?

Say your mothers’ brother is called Simon. Simon has a child and this person is called Dave. Dave is your cousin. Let’s call Dave’s mother (and Simon’s wife) Sarah. Sarah is not related to you by blood. She is your aunt-in-law. Sarah has a sister called Mary. Mary has a child called Bobby. 

Your first cousin Dave is first cousin Bobby. Bobby is your cousin’s cousin, but not related to you by blood. You can call Bobby your cousin-in-law. You are related to Dave because he is the son of your uncle, Simon. Save is related to Bobby through his mother (Sarah). 

For this reason, these relatives are often called cousins in law, but it is also possible to call them cousins by marriage. 

Is my cousin’s cousin my second cousin?

No, they are not. First cousins share a mutual grandparent, and second cousins share great-great parents. The first, second, third, and so on, the degree of cousinhood related to the number of generations between two cousins’ parents, and their nearest common ancestor. 

So, a cousin’s cousin is likely to be of the same generation, making it impossible for this person to be your second cousin.

Is my cousin’s cousin in my family?

It depends. If your cousin’s cousin is part of the same bloodline and you and your cousin are all from the same set of siblings, as is this cousin, then your cousin’s cousin is also your cousin.

If, as per the example above, they are your cousin’s cousin because one of their parents has children from another marriage, then they are not part of your blood family and can be referred to as a cousin-in-law. 

Some people call a cousin’s cousin a distant cousin rather than a cousin-in-law. The main thing to remember is that these cousins can be relatives, but if they are not part of your family tree via blood, then it is easier to refer to them as “in-law.”

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