Cousin

A cousin is part of your family.

They are the children of your aunt or uncle.

You can have many cousins. Some are from your mom's side. Some are from your dad's side.

Some cousins are very close. Others are far away. This happens when you are many years apart.

Some cousins share both sets of grandparents. These are called double cousins. They are related in two ways!

It is fun to have family. Do you have a cousin?

A cousin is a relative in your family.

Most people call the child of an aunt or uncle a first cousin. You can have many cousins. Some come from your mother's side. These are maternal cousins. Some come from your father's side. These are paternal cousins.

Cousins can be close or far apart. We use the word "degree" to show how far apart they are. We also use the word "removal." This shows if cousins are from different generations. For example, a first cousin once removed is one generation apart.

Some cousins are very closely related. Double cousins share both sets of grandparents. This happens when two siblings marry two siblings from another family. Half cousins share only one grandparent.

In some parts of the world, cousins marry each other. This can help families keep their wealth or power. However, being very closely related can change genes. This might lead to health risks for their children. Some people use the term "consanguinity" to measure how closely people are related.

A cousin is a special kind of relative in a family tree. Most people call the child of an aunt or uncle a first cousin. This relationship means you share a common ancestor, but you are not siblings. You are also not the parent or child of that person. In the English-speaking world, the word cousin covers many different types of relatives. This means you might have many more cousins than any other kind of relative.

To be very exact, people use two words: degree and removal. The degree tells you how many generations you are from your shared ancestor. A first cousin is one degree away from that ancestor. Removal describes the difference in generations between two cousins. If one cousin is older, they might be in a different generation. For example, a first cousin once removed is one generation apart. Two people can be removed but still be close in age.

There are many ways to be a cousin. If you are related through your mother, you have a maternal cousin. If you are related through your father, you have a paternal cousin. Some cousins are even more closely related than others. Double first cousins share both sets of grandparents. This happens when two siblings marry two siblings from another family. Half cousins are different because they only share one grandparent.

Scientists and lawyers use special terms to talk about these links. They use a word called consanguinity to measure how close a relationship is. This is often shown as a coefficient of relationship. For first cousins, the consanguinity is one-eighth. If you are a double cousin, your consanguinity is twice as high. This is because you have more shared ancestors. Some people even use the term "kissing cousin" for a distant relative.

In many parts of the world, cousin marriage is a common practice. Historically, as many as 80 percent of marriages were between cousins. Today, about 10 percent of marriages are between first or second cousins. Some people use these marriages to keep wealth or power in a family. However, being very closely related can change how genes work. This can increase the risk of certain health issues for children. In some places, such as the Middle East, these marriages are very frequent.

A cousin is a relative who shares a common ancestor but is not a sibling, parent, or child. In the kinship system used in English-speaking countries, the term "cousin" is a broad category. It includes many different types of relationships based on how many generations separate people from their shared ancestor. Because this single word covers so many different links, an individual can have many more cousins than any other type of relative. Genealogists, who study family histories, can sometimes track hundreds of these relationships across several centuries.

To describe these relationships precisely, people use the terms "degree" and "removal." The degree measures how many generations exist between the cousins and their most recent common ancestor. For example, a first cousin is one degree away from that ancestor. The degree is calculated by looking at the cousin closest to the ancestor and subtracting one. Removal describes the difference in generations between the two cousins. If two cousins belong to different generations, they are "removed." For instance, a first cousin once removed is one generation apart. Two people might be removed but still be close in age if their parents had children at very different times.

There are many specific ways to categorize these relatives. A maternal cousin is related through a mother, while a paternal cousin is related through a father. These relationships are not always reciprocal. One person's maternal cousin might be the other person's paternal cousin. We also use the terms "parallel" and "cross" cousins to describe how they are related. Parallel cousins descend from same-sex siblings. Cross cousins descend from opposite-sex siblings. Some families also use terms like "cousin-uncle" or "cousin-niece" to show if a cousin belongs to an older or younger generation.

Some cousins are more closely related than others due to unique family connections. Double first cousins occur when two siblings from one family marry two siblings from another family. These cousins share both sets of grandparents, making them "doubly related." In contrast, half cousins share only one grandparent because they are descended from half-siblings. There are also step-cousins, who are related through marriage rather than blood. A step-cousin might be the child of a parent's step-sibling or the stepchild of an aunt or uncle.

Scientists use the term consanguinity to measure how closely individuals are related by blood. This is often expressed as a coefficient of relationship. A coefficient of one represents a person's relationship to themselves. For first cousins, the consanguinity is one-eighth. This value decreases as the degree or removal increases. If cousins are half cousins, their consanguinity is half that of ordinary cousins because they share only one ancestor. Interestingly, double first cousins have a consanguinity equal to that of half-siblings. If identical twins both have children with another pair of identical twins, the resulting double cousins are as genetically similar as siblings.

Cousin marriage is a practice that has appeared throughout history and in many different cultures. Historically, as many as 80 percent of all marriages were between first or second cousins. Today, about 10 percent of marriages fall into this category. In some regions, such as the Middle East, more than half of all marriages are between first or second cousins. Anthropologists believe these marriages are sometimes used to strengthen families, conserve wealth, or protect cultural heritage. While some cultures encourage these unions, others attach a strong social stigma to them.

There are biological factors involved in close kinship. When couples are closely related, there is an increased chance of sharing certain genes, including recessive mutations. If both parents share a recessive mutation, it may be revealed in their children, increasing the risk of recessive genetic disorders. However, some research shows a different side to this. A study in Iceland found that couples related as third cousins had the greatest reproductive success. This may be because closer kinship can sometimes decrease the likelihood of immunological incompatibility during pregnancy. Over many generations, however, sustained cousin marriage within a population can lead to increased genetic disorders across the entire group.