What Constitutes a Half Sister?

A sister can make your child's world a little bigger, but explaining the exact nature of the relatedness of your children can be confusing if they do not share two biological parents. If the biological or legal relationship your children share is a little complex, you can rest assured that your children are still siblings, complete with sibling affection and rivalry.

Half-Sister Genetics

Your children are considered biological half-siblings if both share only one parent, according to the American Academy of Pediatrics 1. In a half-sibling relationship, the children can share either a mother or a father. Whether you have had a second child with a new partner, or your child's mother has had a daughter with a new partner, the children are half-siblings. Most half-sibling relationships involve a blood relation 1.

Half-Sibling Similar Relationships

Your child's sister may appear to be a half-sister, but the children may actually be more closely related, according to Stanford's The Tech Museum of Innovation 24. If the fathers of both of your children are brothers or father and son, the children are considered three-quarter siblings. The same is also true if you, along with your mother or sister, have children by the same man. Adoption can also produce half-siblings. If you adopt a daughter, but your first child's father does not, the two children will be legal half-siblings. The same is true if your child's father adopts a girl, but you do not adopt her.

Other Types Of Sibling Relationships

Half-siblings may be confused with other sibling relationships, like step-siblings. If you remarry and your partner has a daughter from a previous relationship, her daughter will become the stepsister of your child. Stepsiblings do not share any blood relation, according to KidsHealth, but are formed through marriage 3.

Life With Half-Sisters

Your child may or may not live with his half-sister, according to KidsHealth 3. The fact that your children share only one parent does not mean that they will be less close than other siblings, according to the American Academy of Pediatrics 1. The age of the children can impact their relationship, and sisters are more likely to compete than children of different sexes. Personalities between half-siblings may be similar, or they may be very different.