Sibling rivalries lead to anxiety, depression and low-self esteem later in life but parents should let children fight it out to avoid causing further psychological damage.
Tired parents may welcome this warning ahead of Christmas Day, when rows over presents and the remote control can heap more stress on those finding the extra washing up and difficult in-laws too much to bear.
A new study has claimed intervention by mothers and fathers can cause long-term emotional damage and found the best thing they can do is set clear household ground rules for their youngsters.
Rivalry: A study has found sibling squabbles can cause long-term damage
Rivalry: A study has found sibling squabbles can cause long-term damage
Nicole Campione-Barr, assistant professor of psychological science, at the University of Missouri, said: 'Although parents may be inclined to step in as arbiters, previous research has found that parents' interventions into adolescent sibling conflict can be detrimental.
'In concert with those prior findings, we believe our research suggests that setting household rules such as 'knock before entering a sibling's room', can be the best means for parents to resolve disputes and avoid appearing to play favourites.