Basic definitions[ edit ] Family tree. Cousins are colored green. Generations are shown by alternating stripes of gray and white. People are related with a type of cousin relationship if they share a common ancestor and the most recent common ancestor is two or more generations away from both people.
For example the second cousin once removed relationship is a second-degree cousin with one removal. The removal of the cousin relationship is the number of generations the cousins are apart. When the cousins are separated by a different number of generations from the most recent common ancestor, the cousin relationship is removed.
The difference between the number of generations for each cousin is the removal. Note that two people can be removed but be around the same age due to differences in birth dates of parents children and other relevant ancestors.
If the cousins are removed, the smaller number of generations to the most recent common ancestor is used to determine the degree of the cousin relationship. If one had to go back two generations beyond the parents great grandparents and the other had to go back two or more they would be second cousins  . Multiplicities[ edit ] Double cousins arise when two siblings of one family mate with two siblings of another family.
This may also be referred to as 'Cousins on both sides. Double first cousins share both sets of grandparents and have twice the degree of consanguinity of ordinary first cousins.
Half cousins are descended from half siblings. The children of two half siblings are first half cousins. If half siblings have children with another pair of half-siblings the resulting children would be double half first cousins. Gendered relationships[ edit ] A maternal cousin is a cousin that is related to the mother's side of the family while a paternal cousin is a cousin that is related to the father's side of the family. Unlike all the other cousin relationships discussed thus far this relationship is not necessarily reciprocal as the maternal cousin of one person could be at the paternal cousin of the other.
Parallel and cross cousins on the other hand are reciprocal relationships. Parallel cousins are descended from same-sex siblings. Cousins that are related to same sex siblings of their most recent common ancestor are parallel cousins. A parallel first cousin is either the paternal cousin on the father's side of the family or the maternal cousin on the mother's side of the family.
Cross cousins are descendants from opposite-sex siblings. A cross first cousin is either the maternal cousin on the father's side of the family or the paternal cousin on the mother's side of the family.
Non-blood relations[ edit ] Stepcousins are either stepchildren of an individual's aunt or uncle, nieces and nephews of one's stepparent, or the children of one's parent's stepsibling. Cousins in law are the cousins of a person's spouse or the spouse of a person's cousin. Neither of these relationships have consanguinity.