Difference Between First and Second Cousins
Table of Contents
Key Difference – First vs Second Cousins
Cousin is a relative with whom one shares one or more common ancestors. In a general sense, the term cousin usually refers to a child of one’s aunt or uncle. However, there are different relationships within the term cousin itself. First cousin and second cousin are two such relationships. The key difference between first and second cousins is that a first cousin is a person who shares the same grandparents as you whereas second cousin is a person who shares the same great-grandparents with you.
CONTENTS
1. Overview and Key Difference
2. Who are First Cousins
3. Who are Second Cousins
4. Side by Side Comparison – First vs Second Cousins
5. Summary
Who is the First Cousin?
First cousin is a relative who shares the same grandparents as you, but not parents. First cousin is usually the child of your aunt or uncle. Look at the following chart to understand this relationship more clearly.
Figure 01: Sam and Bill are first cousins.
Sam and Bill are first cousins; they share the same grandparents Sara and John. But their parents are different. Sam’s father Luke is Bill’s mother Jane’s brother. Thus, Jane is Sam’s aunt and Luke is Bill’s uncle.
It is also important to know the meaning of ‘first cousin once removed‘ when talking about the word first cousin. First cousin once removed is either the child of your first cousin or the first cousin of your parent.
Who is the Second Cousin?
The children of the first cousins have a second cousin relationship. That is, the child of your first cousin is the second cousin of your child. Thus, second cousins share great-grandparents.
Figure 02: Eric and Lucy are second cousins.
In the above family tree, Eric and Lucy are second cousins because their fathers are first cousins. They also share common great grandparents Sara and John.
Some people mistake the child of their first cousin as the second cousin. But, as mentioned above, the child of your first cousin is your first cousin once removed. A second cousin once removed is either a child of your second cousin or the second cousin of your parent. It is easier to remember to remember these relationships by keeping in mind that the phrase ‘once removed’ indicates a generational difference.
The following family chart will help you to identify all the above relationships.
Figure 03: Cousins
What is the difference between First and Second Cousins?
First vs Second Cousins | |
| First cousin is the child of one’s aunt or uncle. | Second cousin is the child of one’s parent’s first cousin. |
| Common Ancestors | |
| First cousins share grandparents. | Second cousins share great-grandparents. |
| Parents | |
| The parents of first cousins are siblings. | The parents of second cousins are first cousins. |
| Cousins once Removed | |
| The first cousin once removed is either the child of your first cousin or the first cousin of your parent. | The second cousin once removed is either a child of your second cousin or the second cousin of your parent. |
Summary – First vs Second Cousin
Cousins are relatives who share one or more common ancestors. The difference between first and second cousin is the distance in the relationship. The first cousin is the child of one’s aunt or uncle. The second cousin is the child of one’s parent’s first cousin. First cousins have the same grandparents whereas the second cousin has the same great-grandparents.
Image Courtesy:
1. “Cousin tree” (Public Domain) via Commons Wikimedia
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