Many different things can cause siblings to fight. Most brothers and sisters experience some degree of jealousy or competition, and this can flare into squabbles and bickering. But other factors also might influence how often kids fight and how severe the fighting gets. These include:
- Evolving needs. It's natural for kids' changing needs, anxieties, and identities to affect how they relate to one another. For example, toddlers are naturally protective of their toys and belongings, and are learning to assert their will, which they'll do at every turn. So if a baby brother or sister picks up the toddler's toy, the older child may react aggressively. School-age kids often have a strong concept of fairness and equality, so might not understand why siblings of other ages are treated differently or feel like one child gets preferential treatment. Teenagers, on the other hand, are developing a sense of individuality and independence, and might resent helping with household responsibilities, taking care of younger siblings, or even having to spend time together. All of these differences can influence the way kids fight with one another.
- Individual temperaments. Your kids' individual temperaments — including mood, disposition, and adaptability — and their unique personalities play a large role in how well they get along. For example, if one child is laid back and another is easily rattled, they may often get into it. Similarly, a child who is especially clingy and drawn to parents for comfort and love might be resented by siblings who see this and want the same amount of attention.
- Special needs/sick kids. Sometimes, a child's special needs due to illness or learning/emotional issues may require more parental time. Other kids may pick up on this disparity and act out to get attention or out of fear of what's happening to the other child.
- Role models. The way that parents resolve problems and disagreements sets a strong example for kids. So if you and your spouse work through conflicts in a way that's respectful, productive, and not aggressive, you increase the chances that your children will adopt those tactics when they run into problems with one another. If your kids see you routinely shout, slam doors, and loudly argue when you have problems, they're likely to pick up those bad habits themselves.
Source: Kids Health