The impacts of typically developing siblings on the developmental outcomes of children with disability: A scoping review.

Kaniamattam et al. (2023) mapped every paper that asked: do typical brothers or sisters change how a child with disability grows up? They swept autism, Down syndrome, cerebral palsy and more.

The team read 40 years of work. They kept studies that tracked any developmental score in the disabled child and also recorded data about a typical sibling.

The short answer: we still do not know. A few small studies hint that an older typical sibling might help language or play skills in autism, but the numbers are too thin to trust.

For every other disability group the shelf is almost bare. Too few kids, too many ways of measuring, no clear picture.

Meltzer (1983) looked at the same question but flipped the camera. That review asked how the disabled child affects the typical sibling. Monica et al. turn the lens back. Together the two papers show we have studied the 'impact direction' unevenly: forty years on typical kids, a trickle on disabled kids.

Mulder et al. (2020) and Amanollahi et al. (2025) ran real sibling-support groups and saw gains in typical siblings' mental health and relationship warmth. Their positive results make the gap louder: we can build programs for typical kids, yet we still lack the evidence to design programs that let those same siblings boost the disabled child's development.

Dumont et al. (2014) found that once family income and stress are held constant, typical siblings of disabled kids look just like any other kid on wellbeing scores. That warning about confounds helps explain Monica's main message: without bigger, better-controlled studies we risk blaming or crediting siblings for effects that really come from poverty, parenting stress, or other family forces.

Before you write 'encourage peer modeling by typical sibling' in a treatment plan, pause. The review says the evidence is not there yet. Use siblings because it feels natural and ethical, but treat it as clinical judgment, not science. Meanwhile, track the data: note if the disabled child gains skills on days the sibling joins. Those single-case data points are the bricks the field still needs.