Parenting

Why Your Kids Turned Out Nothing Alike, According to ‘Raising Good Humans’

October 24, 2025

You can feed them the same snacks, read the same bedtime stories, and hang the same reward charts, but somehow, your kids still end up polar opposites. One’s the rule-follower, the other’s the rebel. One color-codes their backpack, the other forgets they own one.

On Raising Good Humans, host Dr. Aliza Pressman sits down with journalist Susan Dominus, a mother of fraternal twins, to unpack why that happens. Together, they get real about what shapes our kids, what parents can actually control, and the myths making everyone spiral.

Why kids raised in the same household turn out completely different

Studies show that even kids who share 50 percent of their genes and 100 percent of their household can end up wildly different because temperament isn’t something parents can script. As Pressman jokes, “Parents of twins are the first to buy temperament,” realizing fast that they can’t control who their kids are, only how they’re supported. Dominus knows that firsthand. “You feed them the same way, you read the same books to them every day, you have the same reward charts on the refrigerator, they wear the same pajamas,” she says of her twins. And yet one’s the social chair of his fraternity at Wisconsin, and the other is at a tiny great-books college in Santa Fe reading Aristotle.

Researchers estimate 40 to 60 percent of personality traits are heritable, meaning kids come preloaded with their own quirks. Parenting still matters, but mostly in how it guides, not molds. Think of it like this: you’re the Wi-Fi, not the hard drive. You can influence the connection, but the system itself came with its own settings. According to behavioral geneticist Robert Plomin, what really shapes personality differences between siblings isn’t the shared environment, but the non-shared environment: the random mix of experiences, friends, teachers, and moments that only happen to one kid.

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Busting parenting myths that are making everyone miserable

So if temperament is mostly hardwired, what else have we been overthinking about raising kids? Turns out, quite a lot.

Myth #1: Birth order defines your personality

We’ve all heard it: oldest kids are responsible and bossy, middle kids are peacemakers, youngest kids are wild and attention-seeking. It’s such ingrained cultural wisdom that people introduce themselves with their birth order like it’s a personality type.

“People hate hearing this, but it’s true…the oldest children, they may be the most conscientious relative to the younger siblings, but if you put them out into the world in a workplace, they’re not necessarily the most conscientious relative to everybody else around them,” Dominus explains. “Like it doesn’t actually make you more conscientious than you would have been if you were the third child.”

In other words, birth order might affect how you behave within your family, but it doesn’t fundamentally shape who you are in the world. You’re not doomed to be a certain way just because of when you were born.

Myth #2: If you just do the right things, your kids will turn out how you want

“If you think it’s hard to change your child, try changing yourself into the person who could change a child,” Dominus shares from researcher Dan Belsky. “If your kid’s not like gritty and conscientiousness, are you single-handedly going to make your child that way?” The answer, uncomfortable as it is: probably not.

Dominus even laughs at her own attempt at the classic “spend, save, donate” money-lesson system. “You will not be surprised to hear that I failed. Why? Because I can’t do that with my own finances,” she notes. The point isn’t to give up, but to realize parenting isn’t software engineering. You’re modeling, not manufacturing. Research shows 83 percent of parents believe their child’s success reflects on them—no wonder everyone’s stressed. But the truth? Kids become who they are through a mix of wiring, modeling, and their own messy trial and error.

Myth #3: Achievement pressure creates achievement

“What differentiates the kid who feels the pressure to excel because they’re coming from every privilege…is purpose,” Dominus explains. In her book The Family Dynamic: A Journey into the Mystery of Sibling Success, she profiles families who raised multiple high-achieving siblings—not by hovering over report cards, but by grounding their kids in purpose—a sense of meaning, belonging, and contribution bigger than any GPA.

“Achievement for achievement’s sake does not end well,” Dominus emphasizes. She’s right. The Harvard Gazette reports that students at high-achieving schools are two to six times more likely to experience clinical anxiety or depression compared to their peers. And the pressure isn’t just emotional. Michigan State University researchers note that unrealistic standards can spike stress, shrink attention spans, and even lead to unhealthy perfectionism. Meanwhile, a Frontiers in Education study found that students driven by intrinsic motivation and autonomy perform better—and feel better—than those chasing external validation. So no, pressure doesn’t build diamonds, but it does build burnout.

The real win is to help kids connect their effort to a why. Dominus’s research shows that kids raised with a clear sense of purpose—often tied to family values or community impact—grow into adults who know what they’re working toward. Instead of obsessing over outcomes, try focusing on curiosity and effort. Ask what made them proud of their work, not just what grade they got. If they lose a game or bomb a test, talk about what they learned instead of what went wrong. And when they light up over something random—building Legos, writing lyrics, teaching their sibling math—lean in. That spark is usually where purpose hides.

For more insights, tune into Raising Good Humans with Dr. Aliza Pressman, streaming now.