Туысқандық қатынастар мен ата-тектің буындары

Descendant of an ancestor's sibling

A cousin is a relative that is the child of a parent's sibling; this is more specifically referred to as a first cousin. More generally, in the kinship system used in the English speaking world, a cousin is a type of relationship in which relatives are two or more generations away from their most recent common ancestor. For this definition Degrees and removals are used to further specify the relationship. Degree measures how distant the relationship is from the most recent common ancestor(s). If the cousins do not come from the same generation Removal is specified as removal measures the difference in generations between the two cousins. When the removal is not specified, no removal is assumed. Various governmental entities have established systems for legal use that can precisely specify kinship with common ancestors any number of generations in the past; for example, in medicine and in law, a first cousin is a type of third degree relative.

People are related with a type of cousin relationship if they share a common ancestor, and are separated from their most recent common ancestor by two or more generations. This means neither person is an ancestor of the other, they do not share a parent (are not siblings), and neither is a sibling of the other's parent (are not the other's aunt/uncle nor niece/nephew). Basic family tree The relationship between every solid shaded box and a similar one on the other branch of the tree is that of a cousin. The removal is the number of rows by which the relatives are separated. The degree of the relationship is that of the relative with the lowest order. The rules are the same for cousins in law, except they exist between shaded solid lines and shaded dotted lines. For example, David and George are on opposing sides of the family tree and are first cousins (David is of the lowest order: one) with one removal (the cousins are of order one and two respectively; therefore, the difference in generations to the common ancestor is one).

The terms full cousin and cousin german are used to specify a first cousin with no removals. The terms cousin uncle/aunt and cousin niece/nephew are sometimes used to describe the direction of the removal of the relationship, especially in Mennonite, For example, a cousin granduncle is a male first cousin twice removed that comes from an older generation, and a cousin grandniece is a female first cousin twice removed who comes from a younger generation. The term grandcousin is sometimes used for the grandchild of a first cousin, or the first cousin of a grandparent: a first cousin twice removed. The term kissing cousin is sometimes used for a distant relative who is familiar enough to be greeted with a kiss.

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. This relationship is not necessarily reciprocal, as the maternal cousin of one person could be the paternal cousin of the other. In the example Basic family tree, Emma is David's maternal cousin and David is Emma's paternal cousin. Parallel and cross cousins on the other hand are reciprocal relationships. Parallel cousins are descended from same sex siblings. A parallel first cousin relationship exists when both the subject and relative are maternal cousins, or both are paternal cousins. Cross cousins are descendants from opposite sex siblings. A cross first cousin relationship exists when the subject and the relative are maternal cousin and paternal cousin to each other. In the basic family tree example, David and Emma are cross cousins.

Edwin and Frances are double first cousins because they share both sets of grandparents as they are cousins through both parents. They are cousins through the siblings Claudette and Alfred as well as the siblings Henry and Dorothy. Double cousins are relatives who are cousins from two different branches of the family tree. This occurs when siblings, respectively, reproduce with different siblings from another family. This may also be referred to as "cousins on both sides". The resulting children are related to each other through both their parents and are thus doubly related. Double first cousins share both sets of grandparents. David and Penelope are half cousins because they share only one grandparent (Alice) because they are related through half siblings (Anne and Robert). Half cousins are descended from half siblings and would share one grandparent. 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. While there is no agreed upon term, it is possible for cousins to share three grandparents if a pair of half siblings had children with a pair of full siblings.

David and Evangeline are step cousins because David's uncle (Charles) is now Evangeline's stepfather, Evangeline's mother (Claudine) having married Charles. Step cousins are either stepchildren of an individual's aunt or uncle, nieces and nephews of one's step parent, or the children of one's parent's step sibling. A cousin in law is the cousin of one's spouse or the spouse of one's cousin.

Consanguinity is a measure of how closely individuals are related to each other. It is measured by the coefficient of relationship. Below, when discussing the coefficient of relationship, we assume the subject and the relative are related only through the kinship term. A coefficient of one represents the relationship one has with oneself. Consanguinity decreases by half for every generation of separation from the most recent common ancestor, as there are two parents for each child. When there is more than one common ancestor, the consanguinity between each ancestor is added together to get the final result. Between first cousins, there are two shared ancestors each with four generations of separation, up and down the family tree: ; their consanguinity is one eighth. For each additional removal of the cousin relationship, consanguinity is reduced by half, as the generations of separation increase by one. For each additional degree of the cousin relationship, consanguinity is reduced by a quarter as the generations of separation increase by one on both sides. Due to the risk that the trait is harmful, children of high consanguinity parents have an increased risk of recessive genetic disorders. See inbreeding for more information. Closely related couples have more children. Couples related with consanguinity equivalent to that of third cousins have the greatest reproductive success. This seems counterintuitive as closely related parents have a higher probability of having offspring that are unfit, yet closer kinship can also decrease the likelihood of immunological incompatibility during pregnancy.

Cousin marriage is important in several anthropological theories, which often differentiate between matriarchal and patriarchal parallel and cross cousins. Currently about 10% and historically as high as 80% of all marriages are between first or second cousins. Anthropologists believe it is used as a tool to strengthen the family, conserve its wealth, protect its cultural heritage, and retain the power structure of the family and its place in the community. Some groups encourage cousin marriage while others attach a strong social stigma to it. In some regions in the Middle East, more than half of all marriages are between first or second cousins (in some of the countries in this region, this may exceed 70%). Just outside this region, it is often legal but infrequent. Many cultures have encouraged specifically cross cousin marriages. In other places, it is legally prohibited and culturally equivalent to incest. Supporters of cousin marriage often view the prohibition as discrimination, while opponents claim potential immorality.