One thing that has always confused me is how to determine relationships among cousins. I know my parent’s siblings’ children are my first cousins. That’s an easy one. But then you get into second cousins, first cousins, once removed, and second cousins, twice removed. I have always thought that my first cousin’s daughter was my second cousin, and that my mother’s first cousin’s son was my third cousin. Guess what? It turns out I was wrong.
The relationships among cousins are based on a couple of factors:
1) First second, third, forth, etc. cousins are the number of generations there are between you and a common ancestor. For example, first cousins share a common grandparent, second cousins share a common great-grandparent, and third cousins share a common great-great grandparent.
2) The “removed” is the number of generations there are between you and the cousin in question. For example, your first cousin’s child is your first cousin, once removed, and the child of your first cousin, once removed is your first cousin, twice removed.
Are you confused yet? I know I was when I first started looking up this stuff. I spent quite a while reading and rereading the information while matching it up with my own relatives before I finally got it.
I should also mention that if you have relatives that could be a cousin (and any other relationship), the closest relationship is dominant over any other form of relationship. For example, my father’s brother married my mother’s cousin. Their children are technically my first cousins on my father’s side, and my second cousins on my mother’s side. However, the relationship of first cousins is closer than second cousins, and so they are considered my first cousins only.
I found a great tool online that is used for determining the relationship with your cousins. You can find it at iRoots.net.