GeneralGenealogy

What is a second cousin? Family trees, decoded

It’s happened to all of us at some point. You’re the guest of a friend who was invited to their relative’s wedding and at some point in the evening, you get bombarded with introductions to random distant relations. Between the open bar and the dessert table, you’re trying to understand why there are three cousin Katies and what the heck a third cousin twice removed means.

We get it. The whole realm of family relationships is messy. So, let’s break down these confusing degrees of separation.

Do you know how to read a family tree?

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Understanding family relations comes down to knowing how to read a family tree. Even if you’re not a genealogist, you’ve probably looked at a family tree — or created a simplified one in a high school history class. Let’s begin by assuming we’re talking about your grandparents, who will represent the first link as a circle (grandmother) and square (grandfather). And for clarity, we’re focused on your mother’s parents, your maternal grandparents.

So your grandparents have three children — your mom and two sons, who are your uncles. That’s two squares and a circle. Your mom is that circle. She married your father, which creates a link to a square, and your parents have two children, you and your sister. But your uncles also married and have children, which means there are a lot more circles and squares in that family tree.

Breaking down that family tree

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Every time you create a new row of relations on a family tree, that represents a new generation. So, if your grandparents are the first generation, your mother and her siblings are the second. And ultimately, you, your sister and all of your cousins are the third generation. Now in our simplified family tree, we’ve only gone back three generations. But in effect, you can follow a family tree as far back as records will allow you to discover.

How does this relate to cousins?

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Alright, this is where things start to get a little overwhelming, so stick with us here. There are levels of cousins and they depend on the grandparent you share, and the degree of cousin-hood (first cousin, second cousin, etc.) represents which generation links the two of you.

  • First Cousins: Your first cousin is anyone who shares the same grandparent as you. So, if either of your parents has siblings who also had children, those children are your first cousins.
  • Second Cousins: When you share a great-grandparent, that cousin is your second cousin. So, if your grandparents’ parents had siblings with children (and so forth), those relations are your second cousin.
  • Third Cousins: Third cousins share a great-great-grandparent.

This could continue into infinity. Again, you can trace genealogical relations as far as possible, assuming that you can accurately track your lineage. These familial degrees occur on both sides of the family, so just because we used your maternal grandparents as an example doesn’t mean that the same wouldn’t hold for your paternal relations.

What about that “removed” bit?

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Yeah, this is where things can get a little wild. When someone says “this is my second cousin once removed,” it might throw you for a loop, but it’s pretty easy to break down. Remember that your second cousin shares a great-grandparent with you. The “removed” means that they are descended from that second cousin. So a “second cousin once removed” is your second cousin’s child. If they’re a second cousin twice removed, that means you’re talking about your second cousin’s grandchild.

What does this all mean?

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It means that family trees can get unwieldy. One of the best ways to keep track of your relations and their degrees of separation is by keeping an accurate family tree. While you might not be Johnny on the spot at the family reunion, when your head clears and you check those relations against the family tree, it’ll all come into focus.