Favoritism hurts every child in the family — not just the unfavored one

It's not just the "unfavored" child who suffers

Favoring one child over another is rarely intentional. It happens for many reasons — one child is easier to be around, another needs more attention because of behavioral problems, or a bond just forms more naturally. But a longitudinal study published in the journal Child Development suggests the damage from this "differential parenting" doesn't stop with the child who gets the worse deal: it harms every child in the family.

The study, carried out at the University of Toronto with researchers from McMaster University and the University of Rochester, looked at almost 400 Canadian families with children whose average age ranged from 2 to 5. Unlike earlier research, which typically studied only sibling pairs, this one included up to four children per family and used statistical techniques designed to separate effects that operate across the whole family from those hitting individual children.

"Past studies have looked at the effects of differential parenting on the children who get more negative feedback," explained lead researcher Jennifer M. Jenkins, Atkinson Chair of Early Child Development and Education at the University of Toronto, "but our study focused on this as a dynamic operating at two levels of the family system: one that affects all children in the family as well as being specific to the child at the receiving end of the negativity."

How the damage spreads

The team measured differential parenting — being more positive with one child and more negative with another — through both mothers' reports and observation in the home. They found that uneven treatment was associated with more aggression, attention problems, and emotional problems in children. The home environment itself becomes more hostile: sibling relationships deteriorate when children perceive that one of them is the clear favorite.

The study also found a troubling pattern in who treats children differentially: the more risk factors mothers faced — less education, lower income, single parenthood, poorer mental health, a history of abuse — the more likely they were to treat their children unequally. Outside stress, in other words, makes fairness harder.

What parents can take from it

The finding is not an accusation — Jenkins and her colleagues frame it as a stress problem, not a character verdict. When resources and support are thin, even-handedness is one of the first casualties. But the study does put a name on something children already sense: kids are highly perceptive about how they are treated relative to their siblings, and even the favored child grows up in a household poisoned by resentment.

The practical takeaway is awareness. Notice when one child is drawing most of your anger, ask whether the reaction is really about what that child did — and pay attention to the "it's not fair" protests. They are, often, a child saying they feel unloved.

Archive summary, February 2013, based on the Society for Research in Child Development's release for Jennifer M. Jenkins et al., Child Development.