While children may try to preserve relationships with friends by avoiding conflict, sibling relationships, because they don't operate under the same threat of termination, are likely to experience a greater frequency of both intense warmth and conflict. Parents need to recognize that siblings may experience a certain amount of conflict, competition and rivalry. However, if these battles occur within a supportive sibling relationship, they help children learn that positive relationships don't just happen, but rather must be built. Children's greater familiarity with their brothers or sisters provides them with an environment where they can learn appropriate interpersonal skills in preparation for the interactions they will have outside the family, particularly with peers. Within their sibling relationships, children can learn the likely implications of their behaviors on children outside the family.
Siblings can have an impact on one another for both good or ill.
For example, older siblings' involvement in illicit drugs and alcohol, as well as deviant and sexual behavior, have all been predictive of younger siblings' involvement in similar behavior. In contrast, brothers and sisters have also been found to provide a protective buffer for one another when having to face such negative experiences as divorce or difficulty in establishing good friendships. As siblings grow their relationships are likely to change. During childhood, siblings experience an increase in conflict and a reduction in support that continues until it peaks at around ages 12 to 13 years old. This is followed by a continued increase in support and decrease in conflict as siblings move into middle to late adolescence.