Research from the University of Delaware reveals that birth order and sibling sex composition significantly shape how teenagers manage stress, challenging traditional assumptions and highlighting the importance of family bonds in resilience.
A new study from the University of Delaware suggests that sibling relationships and birth order can shape how teenagers cope with stress, but not always in the ways parents or researchers might expect. The work, published in Behavioural Sciences, analysed data from nearly 1,500 adolescents in the north-east of the United States and found that the effect of being older or younger depended heavily on whether siblings were the same sex or mixed sex.
Mellissa S. Gordon, an associate professor in the university’s College of Education and Human Development, said the research grew out of her own experience as the eldest child in a family where she often acted as a guide for younger siblings. The study, co-authored with Megha Garg and Christine M. Ohannessian, set out to test whether older siblings would be more likely to use coping strategies such as active coping, distraction or problem-solving, and whether same-sex sibling pairs would show stronger modelling than mixed-sex pairs.
The results were more nuanced than expected. In same-sex sibling pairs, birth order was not linked to any of the coping styles measured. In mixed-sex pairs, however, older siblings were more likely to use coping strategies, a finding the researchers described as new. The pattern also shifted by coping type: when the adolescent was the older sibling, being in a same-sex pair was associated with lower use of active and problem-focused coping, while younger siblings showed no clear birth-order effect.
The findings fit with a wider body of research showing that sibling ties matter in adolescence, a period when young people spend a large share of their time with brothers and sisters. A separate study on parent-child communication and early adolescent coping, published in the Journal of Child Psychology and Psychiatry, found that both maternal and paternal communication were linked to coping styles and that sibling relationship quality helped explain those links. Another paper in Behavioural Sciences similarly concluded that sibling support can shape how adolescents respond to stress, reinforcing the idea that family relationships work together rather than in isolation.
Gordon said the practical lesson for therapists, school psychologists and counsellors is to look beyond the individual child. Her team argues that sibling relationships, including birth order and sex pairings, should be part of routine assessment when adults are trying to understand how a teenager handles pressure. The broader message, the researchers say, is that open communication at home and supportive sibling bonds can strengthen resilience, encourage problem-solving and help adolescents avoid facing difficulties alone.
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