Adult children guessing which sibling their mother favors get it wrong roughly 60% of the time, according to Purdue University’s newsroom summary of Professor Jill Suitor’s parental favoritism research. Most mothers do have a favorite. Most adult children think they know who it is. Those two things turn out to be only loosely connected.
The research behind that finding comes from the Within-Family Differences Study, a project Suitor has run for more than two decades with National Institute on Aging funding, tracking hundreds of families and, across its full run, more than 1,700 family members. It’s one of the longest-running academic efforts to answer a question most families dance around at Thanksgiving: does Mom actually have a favorite, and if so, who?
The Numbers Behind “Mom Has a Favorite”
An earlier phase of this same research line, conducted by Suitor with Cornell’s Karl Pillemer and published in the Journal of Marriage and Family, interviewed 275 Boston-area mothers in their 60s and 70s alongside 671 of their adult children. The results were direct: 70% of mothers named a specific child they felt emotionally closest to, 79% named one child as most likely to provide care if they needed it, and 73% identified one child they had more conflict with than the others, according to NBC News’s reporting on the published study. Only 30% of mothers said they had no preference across any of those categories.
Adult children, for their part, were far less willing to believe their mother was neutral. Only 15% of adult children thought their mother showed no favoritism at all — half the rate mothers themselves reported. Kids are more convinced a favorite exists than mothers are willing to admit one does, and the study suggests they’re generally right that some form of differentiation is happening. Where they go wrong is naming which sibling it actually is.
Why Guessing Is So Hard
Part of the mismatch comes down to mothers rarely announcing their preferences out loud. Favoritism in this research shows up as an internal ranking mothers hold and researchers extract through structured interview questions, not something communicated directly to the children involved. Without that direct signal, adult children are left inferring favoritism from circumstantial evidence: who gets called first, who visits more often, who seems to get away with more. Those signals can be misleading, because the reasons behind a mother’s closeness to one child aren’t always the reasons a sibling would expect.
Suitor’s broader body of research has found that the specific child favored often shifts depending on the category in question — the child a mother feels closest to isn’t necessarily the one she’d trust most for caregiving, and the child she has the most conflict with isn’t necessarily the one she feels least close to. A related paper from Suitor’s research group found that mothers’ explanations for favoring a particular child often centered on birth order and life circumstances — the youngest, the one who needed the most support, the one who stepped up during a health crisis — reasons that don’t always track with the sibling stereotypes families tend to settle into over the years.
The Stakes Are Higher Than a Guessing Game
This isn’t purely academic curiosity. Suitor’s research, per the same Purdue summary, found that adult children who saw themselves as the most disappointing child in the family showed a stronger link to depression than almost any other factor the researchers measured, second only to the child’s own physical health. Misreading where a parent’s preferences actually sit doesn’t just produce wrong guesses at a family gathering. It can shape how an adult child feels about themselves for years, based on an inference that the data suggests is more often wrong than right.
The honest takeaway from two decades of this research isn’t that mothers are playing favorites in some calculated way. It’s that favoritism is real, multidimensional, and largely invisible from the outside — which means the sibling everyone in the family has quietly assumed is “the favorite” may not be the one the data would actually back up.
What Families Do With This
None of Suitor’s published work argues that parents should force themselves into treating every child identically, or that unequal closeness is inherently a failure of parenting. Families are made of individuals with different needs, different life stages, and different relationships with each parent, and some amount of differentiation is close to unavoidable across a lifetime. What the research does argue for is more direct communication than most families manage — because the alternative, silently guessing and quietly building resentment or self-doubt around a wrong guess, is measurably worse for the people involved than an honest conversation would be.
That’s a useful reframe for anyone who’s spent years assuming they know exactly where they rank in their own family. The data says the odds of that assumption being accurate are worse than a coin flip. The sibling everyone agrees is “the favorite” might simply be the one who’s easiest to notice — not necessarily the one the numbers, or the parent, would actually pick.
