How does the cousin system work?

-hey I have a friend and we might be related. He has the same last name as the maiden name of my mother. We have done family research and it turns out my great grandmother was related to his great grandad through third cousins or second cousins. So what does that make the relation between me and my friend? In addition, my half brother has a cousin on his dads side (not my dad) that is married to my friends third cousin, does that make us related that way?

Thanks for the help I really could do with this clearing up :)Instead of attempting to organize the question, I suggest that you download and print a genealogical relationship chart. There are several sites that have them about Genealogy.com is one. Then you can review each relationship yourself. You should not attempt to ask a question about cousin relationships

and mix the lineage. Start with one side. I believe this question may be about your Maternal line, but am not sure because of you addition, which makes it sound like you believe your half brother fathers may be related to you in some way, which is usually not the case since his father is not your father.
Cousins are based on if you share an ancestor, such as a grandparent. If you share parents, you are not cousins, you are siblings. Your parents siblings are aunts or uncles. The children of your immediate blood aunts and uncles are your 1st cousins.

When you get past grandparents, such as sharing a gr gr gr grandparent, there are degrees of cousinship. If you have the SAME gr grandparent, it makes you 2nd cousins. If your grandparent is someones gr grandparent, then you are 1st cousins, one (generation) removed. If your friend's gr grandfather was your gr grandmothers actual cousin of some degree, then they share an ancestor, and your friend and you will also share that ancestor. The key is having ancestry which is the same.

This does not apply to your brother's cousin. His cousin is because they have a common ancestor. You don't have the same common ancestor, so there is no relationship.

Marriage connects people to a limited extent, but it does not make persons descend from the same persons. Connected isnt the same as related.
Ted has a great answer.



Now you said it turns out your great grandmother was related to his great granddad through third or 2nd cousins. So I am not exactly sure what you mean. Your cousins' cousins are not necessarily related to you. That would be true for your great grandmother. She had cousins who were children of her parents' siblings but the only family of her aunts and uncles by marriage that were related to her were the children, grandchildren etc they had by her aunts and uncles they have who were siblings to her parents.



Here is a relationship chart.



http://www.islandregister.com/cousin.htm鈥?/a>



Where a lot of people get off in determining cousin relationships is they don't understand the "removes' which comes in when you are in a different generation coming down from a common ancestor. For instance your parents' first cousins are your first cousins once removed as their grandparents are your great grandparents. Thus one generation different. Also you are a first cousin once removed to your first cousins' children as your grandparents are their great grandparents.



Edit: However even if he is related to you it seems to be far enough distant that you can go ahead and flirt with him.