The next two articles will focus on how to determine kinship (consanguinity) between two people. Throughout time kinship relationships were important for both determining royalty lines as well as preventing two people that were closely related from marrying. Today plotting out kinships is used in genealogical DNA studies.
There are three ways to record a kinship relationship between two people; the Germanic method or canon law, the Roman method or civil law, and the common method.
The canon law measures the maximum number of steps from the nearest common ancestor. For example, it takes two steps to get from me to my grandfather. It also takes two steps for any of my first cousins to get there. So, our canon law degree is two. If you are looking at two individuals that are from different generations then you use the greater number of steps as your canon degree. For example, it takes three steps to get to my great grandfather. It only takes two steps for one of my uncles to get there. Our canon law degree is three.
The civil law represents the total number of steps that separate two individuals. From me to my grandfather is two steps; from my grandfather back down to my first cousin is two more steps. So, my first cousin and I have a civil law degree of four. Going from me to my great grandfather is three steps; from my great grandfather back down to my uncle is two steps. Our civil law degree is five.
The common method is the one that most people are familiar with. It uses the terms aunt, uncle, grandmother, grandfather, cousin etc. However, some people get a little confused when it comes to figuring out if someone is "removed" or not. The term removed is only used with cousins. The terms first cousin, second cousin, third cousin etc. refer to individuals in the same generation. For example, the children of two siblings are first cousins. The children of those two first cousins are second cousins. The children of the two second cousins are third cousins and so on.
The term removed refers to two individuals that are in different generations. Think of it as moving diagonally in a family tree. For example, my first cousin's child and I are first cousins, once removed. If my first cousin has a grandchild then that child and I are first cousins, twice removed. If my daughter and my first cousins' daughter (they would be second cousins) both have children then their children would be third cousins. However, my daughter and her second cousin's child would be second cousins, once removed. It follows a completely logical pattern which is easy once you get the hang of it.
The good news is that most computer genealogy programs calculate all three methods of kinship with a simple mouse click. However, it is a good idea to understand how to do it by hand.