It is a universally acknowledged truth that parents aren’t supposed to have a favorite child. They are supposed to dole out unconditional, unwavering doses of love in identical portions and keep personal preferences out of it. It is a long-standing cultural perception that impartiality is the default setting for most parents – but is this possible? Are parents, who are mere mortals, capable of loving objectively?

The answer is complicated, steeped in generations of family dynamics, and varies wildly depending on perspective.

I interviewed dozens of parents, asking them if they had a favorite child, and I learned there are a plethora of facets to this issue. Many parents felt an affinity for the child they had the most in common with, or they enjoyed certain activities with one child more than another. Many had a preferred age, like toddlerhood or preteens, and relished time within those parameters. Some identified with the child with corresponding birth-order or took up for the underdog. Other parents said their affection was largely based on need, thus proving the squeaky wheel theory. Several said they gravitated toward the child who exhibited good behavior and respect. Some joked they liked the kid who slept most, and a handful of parents private messaged me and confessed they simply enjoyed one child’s personality more than the rest.

As diverse as the responses were – and the storied reasons behind them – the underlying consensus was that love and favoritism are separate entities. Parents maintained, across the board, that the love they felt for their children transcended any preferential treatment or inequities, and they insisted that while they may spend more time with one child, the distinction was quantitative, not qualitative. Even the parents who fessed up to playing favorites said their love remained constant. Love, it seems, comes from devotion and loyalty intrinsic to the parent/child relationship, whereas favoritism implies a conscious choice.

When I asked the very same parents if they had been loved and treated equally by their own parents, the love/favoritism, quantitative/qualitative means of measurement became a distinction without a difference. All but two claimed their parents had favorite children, and they cited time spent together as proof. They also said being on the receiving end of subjective treatment was “shaping” in terms of their parenting styles, and witnessing the fallout between siblings, who vied for attention, made a lasting impact they vowed not to repeat.

These parents presented two very different interpretations of the primary familial bond, which influences all future relationships. Has parenting changed that drastically in one generation, going from favoritism being commonplace when we were kids to now, when it’s considered damaging and indulgent? Or are our true feelings regarding our children – like those of our parents – simply more transparent than we realize? Only our children will be able to answer this for sure, but it’s likely we are inflicting the same damage we suffered, regardless of our attempts at egalitarianism.

Science says it’s futile, anyway. We are designed to pick a favorite child – usually the first born – and we are instinctually driven to ensure her success. It is a Darwinian survival-of-the-fittest scenario: The first born receives the most attention, nourishment, and emotional energy, therefore parents are biologically compelled to protect their investment. After the first child, it is reported that parents become more relaxed about things like about hygiene, nutrition, and safety, and are less attentive to developmental and educational needs. (Not an earth-shattering revelation, by any stretch.)

Does this benign neglect translate into favoritism?

It can. Countless studies establish behavioral correlations to sibling birth order, for example higher academic performance in first-born kids and more reported suspensions in middle children. There is also evidence suggesting gender triggers a classic biased response in parents, tipping the scale in favor of either a son or daughter. Cultural, socioeconomic, and religious factors can contribute as well.

Modern parents, though, have intentions beyond tribalism or propagation of the species. Unlike cave-dwellers who weighed dependency against survival odds and acted accordingly, our objective is to raise healthy, happy kids who are each equipped to succeed in life. We make conscious decisions and don’t rely solely on instinct, we recognize preferential trends in our own families, we see the negative results of favoritism between adult siblings, and we can deliberately change course for the better. Being aware of our predisposition to play favorites makes it easier to avoid.