BY_THE_NUMBERS

The Science of Family Favoritism: What the Research Actually Shows

Most parents insist they love their children 'the same.' Decades of research on parental differential treatment — led largely by sociologist Jill Suitor's long-running studies of Boston-area families — tell a more complicated story: most mothers privately do feel closer to one child, most are reluctant to admit it outright, and their adult children are often wrong about who it is. Meanwhile, the popular idea that birth order itself explains personality — the bossy firstborn, the rebellious baby of the family — has been tested across tens of thousands of people and mostly hasn't held up. What predicts adult wellbeing isn't your slot in the birth order, but whether you felt, or still feel, singled out. Here's how the science moved from folk theory to family surveys.

~70%of mothers interviewed named a specific child they felt closest to — despite most being visibly reluctant to admit favoring anyone at all 39%of adult children correctly identified which sibling their mother actually favored — barely better than chance in most families, and worse than that among children who weren't the favorite ~15%of adult children in the depressive-symptoms study perceived that their mother treated all her children equally — the large majority perceived some form of differential treatment 20,000+people across Germany, the US and Britain analyzed in the largest test of birth-order effects on personality to date — finding no meaningful effect on any Big Five trait

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