How to Work Out Cousinship

Working out how people are related to each other vexes many people tracing their family tree. Anyone (with the exception of brothers and sisters, of course), who shares the same blood descent from the same ancestor, is a cousin. However distant the connection, it is enough to say that you are cousins.

There are more precise terms, however, that you can use.

If you and person X have a grandparent in common, you are first cousins.

If you and person X have the same great grandparent, then you are second cousins.

If you and person X have the same great great grandparents, then you are third cousins.

In all cases, drawn a simple family tree, starting with the ancestor, then their two children from whom you and X descend, and then their descendants in your relevant lines. Make sure each generation lines up.

Where things becomes complicated is when cousins appear on different levels. The way of expressing cousinship in these cases is by the term ‘removed’. If Y is on a different level to you, ie, they are closer or further away from the common ancestor, they are your ‘- cousin – removed’.

If the difference in generations is one, whether up or down, then they are once removed.

If the difference is two generations, whether up or down, then they are twice removed.

For example, you and X are first cousins. X has a child, Y. Y is therefore one generation down from you. Y is therefore your first cousin once removed.

If Y then has a child, Z, then Z is two generations down from you, so Z is your first cousin twice removed.

Remember, that the term ‘removed’ does not take into account whether you are moving up or down the family tree – this is a failure of the system. Therefore, your second cousin’s parent (by which I mean the parent through whom your cousinship is derived) and your second cousin’s child are both your second cousins once removed.

People find the system difficult to grasp because sometimes you have to imagine relatives who do not actually exist. Say your parent has a second cousin, A. To work out your cousinship to A, you must look straight across the family tree to the position below A. A may or may not have a child – that is irrelevant. The existent or non-existent child is, or would be, your third cousin. A is one generation removed from that position, so A is your third cousin once removed.

The foregoing works when you are describing how someone else is related to you. If you want to describe the same relationship from their point of view, ie, how you are related to them, then you need to look at the family tree from their point of view.

Clearly, this does not affect direct cousinships on the same levels of the family tree. You are your second cousin’s second cousin, for example. Where it becomes complicated, again, is when there is a difference in the generations.

Say your first cousin X has a child, Y. Y is your first cousin once removed, as we have seen above. But if you want to describe the situation from their point of view and say ‘I am Y’s …. cousin’ you must start with their position on the family tree.

From Y’s point of view, they are looking across the family tree, on their line, at the space directly below you. If you have a child, then that child is Y’s second cousin, but whether or not you have a child is irrelevant. What is relevant is that you are one generation removed from that position. You are therefore Y’s second cousin once removed.

As long as you write this down as a simple chart, keeping everyone on the right generational level, you will not go wrong. First you go straight across the chart to work out the cousinship, and then up or down the generations to work out by how many degrees removed you are.

There is a chart explaining all this at the front of the 2008 edition of my book Tracing Your Family History.

This explanation is copyright of Anthony Adolph. It may be reproduced freely provided you acknowledge Anthony Adolph as the author.

Of course, this is all irrelevant if you have not traced much of your family tree, so hire me to start investigations today: click here for more details.

“Thank you for the clearest and easiest explanation of the cousin family tree! Very much appreciated!” – Ann Garry, via e-mail (May 2014)