The Science of Raising Kids in Blended Families

Nathan Wallis
The step-parent can see things much more objectively because we don’t see our stepchildren with the rose-tinted glasses. So you often are, as a step-parent, right, and you can call them on it.

But there is a reason why we see our children with rose-tinted glasses. It’s like you keep seeing them as wonderful, and they eventually become wonderful.

Laura Jenkins
In The Blend is a podcast series that helps parents and step-parents navigate life in a blended family. Join me as I speak with experts and guests to get practical advice on how to create a more harmonious blended family life.

Having grown up in a blended family and now a decade into raising one of my own, I bring a personal perspective to these conversations, and we dive deep into the unique dynamics, logistics, and challenges of raising a blended family. From new partners to juggling mixed finances, we will help guide you through it.

Welcome back to In The Blend! I am very excited to bring you this episode with a guest who has an incredible wealth of knowledge when it comes to child development—Nathan Wallis.

Nathan is a neuroscience educator who specialises in how children’s brains develop and what that means for parenting, particularly in blended families.

In our conversation, Nathan breaks down the critical stages of brain development—especially those first 1,000 days—and how these early experiences shape a child’s emotional and social well-being. He also shares why predictability is so important for a child’s brain and offers practical strategies for fostering healthy relationships and emotional regulation.

We also explore the role of communication, validation, and how parents can best navigate discipline and external relationships in blended families.

There are so many gold nuggets in this episode, and I know you’ll walk away with valuable insights that you can apply in your own family.

So let’s dive in.

Well, welcome, Nathan! Thank you so much for joining me today on the show.

Nathan Wallis
Oh, happy to be here.

Laura Jenkins
You have quite a unique background in child development and neuroscience.

Could you start by sharing some of the key stages in a child’s brain development, particularly those that might influence how they adapt to some of these big life changes—like joining a blended family?

Nathan Wallis
I mean, you can’t go past the first 1,000 days.

The 1990s were called the decade of the brain because we learned so much in that time—about as much as we had learned in the previous 300 years.

And probably the biggest discovery was the concept of the first 1,000 days.

That’s from conception—so it includes pregnancy—through to about two and a half years old.

During this time, your brain is basically interacting with the environment to determine what sort of brain you’re going to need for the rest of your life.

So yes, genes are important, but genes only make up 50% of your outcomes. The literature summarises this by saying:

“The human brain is designed to be moulded by the environment it encounters.”

Most animals are set in their genes in a way that humans aren’t.

For example, if you take a camel from the desert and move it to a place with snow and ice, it doesn’t suddenly adapt—it dies. It has to live in a hot climate.

But humans are different. Less than 30% of your genes are set when you’re born. That means over 70% of your genome is designed to be shaped by the environment before deciding which genes are actualised and to what extent.

So, in plain language:

You could take a human baby who comes from generations of desert-dwelling ancestors, move them to a snowy climate, and not only will they live—they will thrive.

That’s because 70% of their genome allows them to adapt to their environment.

So I can’t say enough about those first 1,000 days.

Statistically, we can predict most of your outcomes for the rest of your life by age three—because by then, your brain has formed a foundation based on what you’ve experienced.

I don’t know how much detail you want, because I could talk about this for hours. But the short version?

Language is the major driver of cognition.

The more you are spoken to in those first 1,000 days, the better your cognitive and social outcomes will be.

The more isolated you are, the worse your outcomes.

Laura Jenkins
That is super interesting—I’ve never heard that before!

Nathan Wallis
Well, here’s the cheat sheet for parents:

The more words you speak to your child per day, the better their outcomes.

We can even statistically predict how much money a child will earn at age 32—based on nothing else other than the number of words spoken to them per day by their primary caregiver from birth to one year old.

Language is everything.

So if you want to give your child the best start in life?

Just talk to them.

Forget about high school grades—it’s all sorted by then. The real work happens in babyhood.

Laura Jenkins
I love that.

Now, in a blended family situation, children often need to form bonds with new family members, like a step-parent or a step-sibling.

And by that stage, it’s quite likely that they’re past that 1,000-day period.

Nathan Wallis
If they’re still in that first 1,000 days, it’ll be nice and easy. They’ll probably be looking for that connection quite happily.

Laura Jenkins
Exactly, exactly.

So, what does science tell us about how these relationships can impact a child’s emotional and social development after that 1,000-day mark?

Nathan Wallis
There’s a wide range of responses.

You can have step-siblings who become inseparable, and you can have step-siblings who despise each other—and everything in between.

The way parents approach blending the family plays a big role.

Does the child feel heard? Do they feel like they have a voice?

Because often, it’s Mum and Dad who have fallen in love—but the kids have just been dragged along for the ride.

They don’t always have a say in the situation.

So if they don’t like their new step-parent or step-sibling, you have to validate that feeling. Let them talk it out.

I personally could not stand my stepfather. But that didn’t mean my mother had to leave him.

Every family is different. The key is listening to your kids and giving them some agency.

For example, when blending a family, don’t just throw kids into the same bedroom without their consent.

Talk to them. Ask them:

• How do you feel about this?
• What would make this easier for you?

And, probably most importantly—make sure they still get one-on-one time with their biological parent.

That doesn’t mean hours and hours—it can be as little as 10 minutes a week.

It’s not about the amount of time.

It’s about predictability.

Even if it’s just 10 minutes once a week, what matters is that the child knows it’s coming.

If they know, “Mum and I have our special time every Thursday at 4 o’clock,”—that anchors them emotionally.

And honestly? That makes all the difference.

Laura Jenkins
It’s all about the routine.

Nathan Wallis
It is, yeah.

Absolutely.

Routine is your brain’s best friend.

Laura Jenkins
Yes. So then, for children who are moving between two households, they might have different routines in each home and be exposed to different parenting styles as well.

What are some strategies that parents can use to provide consistency and security in their home?

Nathan Wallis
First of all—they don’t actually need to be consistent.

A lot of parents worry about this, but the truth is, children don’t need a single, unified framework across households.

Kids naturally adapt their behaviour to different people.

They already know:

• What works at Nana’s house doesn’t work at Mum’s house.
• What I can ask Dad for, I wouldn’t ask Mum for.

They learn these separate relationship rules all the time, so they’re already used to it.

That said, it is good for children to have some degree of continuity between homes.

One of the most helpful things?

Let your kids see you and your co-parent being friendly—even if it’s just for five minutes at changeover.

It normalises the idea that their two homes aren’t in conflict.

Also, small rituals can help.

For example, bedtime might be earlier in one house than the other, and that’s fine.

But something like, “At dinner, we all say the best thing that happened in our day before we eat,”—that’s an easy ritual to maintain across both homes.

And when you’re introducing these things, make it easy for the other parent.

They might have limited capacity or interest in adopting traditions from your home—so pick small, meaningful things that don’t feel like a huge effort.

Laura Jenkins
Yeah. Great advice.

Let’s move on to children’s emotional needs.

This comes up a lot in blended families, especially when children struggle with loyalty binds or divided attachments as they move between homes.

From a neurological perspective, how can caregivers better recognise and support these emotional needs?

Nathan Wallis
Are you asking how to make sure the child stays emotionally well, even if they’re unhappy about the situation?

Laura Jenkins
That’s right.

Nathan Wallis
We often talk in mental health about the importance of getting things outside of your head.

The truth is, you don’t always have to solve a child’s problem.

Sometimes, just saying it out loud is 90% of the solution.

So, the key is to create a safe space where they feel free to express how they feel.

Let’s say your child says:
“I feel like you don’t love me as much when Charlotte comes over because you like her more.”

Instead of shutting it down or saying, “That’s not true!”—let them get it out.

You can say:
“I’m sorry you feel that way. That’s not how I see it—what makes you feel like that?”

The most important thing is that they feel heard.

As parents, we’re often too quick to correct. We hear something like that and immediately jump in with:

• “That’s not true.”
• “Don’t be rude.”
• “You shouldn’t feel that way.”

So they never get to express their feelings.

To help with this, I always recommend having a predictable space where kids can talk freely.

For example, in my house, my kids knew that if we were in the garage, they could say whatever they wanted.

They weren’t going to get in trouble for what they said in the garage.

My son actually initiated this—he saw his friends having deep, open conversations in the garage and wanted the same space with me.

At first, he just swore for a whole day because he was testing the boundary.

But eventually, it became a trusted space where he could open up about real things.

The key takeaway?

It doesn’t have to be a garage—but having a designated safe space or time where kids can speak freely is game-changing.

Laura Jenkins
Oh, I love that.

It reminds me of two things.

One, I had another guest on the podcast who talked about a similar garage rule—but for adults!

She told one of her clients that they were only allowed to talk about their ex-wife in the garage.

Anywhere else in the house? Off-limits.

And it worked! It helped them set a boundary on how much time they spent dwelling on it.

Nathan Wallis
That’s actually a brilliant strategy.

It’s so easy to obsess over an ex, and it just takes away your own quality of life.

Even if you think your ex is a complete nightmare, it doesn’t help you to ruminate on it all the time.

So having boundaries, like “This conversation only happens in the garage”, is a fantastic way to compartmentalise it.

Laura Jenkins
Exactly!

And the second thing I was thinking about is the worry list—a strategy I’ve read about before.

You write down everything you’re worrying about onto a list—and then once it’s out, you move on with your day.

Nathan Wallis
Oh, that’s a brilliant practice.

And it’s actually very neurologically sound.

Your brain is trying to problem-solve when it ruminates.

But if you don’t channel that properly, it just keeps spinning in loops—which is what leads to anxiety and depression.

So, doing something simple like writing things down allows your brain to file it away and say:

“Okay, I’ve addressed that. Task complete. Move on.”

It’s incredibly effective for emotional regulation.

Laura Jenkins
Definitely.

So when it comes to emotional regulation, is there anything else you’d suggest outside of routine and safe spaces?

Any other strategies for supporting a child’s ability to self-regulate?

Nathan Wallis
Yes—screen time.

Social media over-activates the brain’s emotional processing centres, making kids more reactive.

Research shows that if a child has just two hours a day of device-free time, it takes them out of the at-risk group for anxiety and depression.

That’s it—just two hours a day.

You don’t have to ban screens completely—but having a set tech-free period (for example, from 4–6 pm daily) can dramatically improve their emotional regulation.

Laura Jenkins
That’s fascinating.

Screens are such a big factor in kids’ lives today.

Nathan Wallis
They are!

But the goal isn’t to eliminate them—it’s just to use them responsibly.

Laura Jenkins
Absolutely.

Any other science-based strategies for making children feel safe, supported, and understood?

Nathan Wallis
Yes!

One of the most powerful things you can do is encourage your kids to have strong relationships outside the home.

I had an auntie and a nana who I was very close to, and those relationships were key to my resilience.

Sometimes, kids find it harder to open up to parents because parents are also the rule enforcers.

But if they have another trusted adult, like an aunt, uncle, grandparent, or family friend, they’re still getting things out of their head—which is the main goal.

And as a parent, you shouldn’t be threatened if your child confides in someone else.

If your child feels comfortable opening up to your sister, for example—be grateful!

Because they’re talking to someone you trust, and that’s a huge win.

Laura Jenkins
Yeah, and your sister—she’s not going to go and spill everything back, but she’ll let you know if there’s anything serious to be concerned about.

Nathan Wallis
Exactly.

She’ll keep your child’s confidence, but she’ll also give you a heads-up if something truly needs your attention.

So fostering those external relationships makes children more resilient.

Another big one? Giving them responsibility.

Kids who have age-appropriate responsibilities—whether it’s earning pocket money, helping with chores, or being responsible for something meaningful—develop a sense of contribution and adulthood.

And lastly, children need opportunities to articulate themselves.

That’s why rituals around family conversations are so important.

For example, at dinner, we used to go around the table and say:

• What was the best thing about your day?
• What was the most surprising thing about your day?

Now, I used to include “What was the worst thing about your day?”—but I actually don’t think we need to focus on the negative as much.

So just doing those simple rituals creates a space where kids get to practice articulating their thoughts and emotions—which is a critical skill.

And honestly? You’d be amazed at what they come out with.

Laura Jenkins
Yeah, I love that.

And in a blended family context, it gives both stepchildren and biological children a chance to share a glimpse into their day—and also hear from the two adult figures in the household.

That’s such a great one to remember.

And I also love your point about building a village—leaning into all the people in your world as important figures in a child’s life, whether they’re your biological child, your stepchild, or someone else entirely.

Nathan Wallis
Yeah, exactly.

And another key thing in blended families?

The birth parent should handle the discipline.

Laura Jenkins
Yes!

Wallis
I’ve found that in blended families, one of the biggest mistakes is when the step-parent takes on the disciplinarian role.

Now, of course, as a step-parent, you can see things much more objectively.

You don’t have the same rose-tinted glasses for your stepchildren that their biological parent does.

That can be useful—because sometimes, you’re actually right about what needs to be addressed.

But there’s a reason why biological parents tend to overlook things or go easier on their kids:

It’s actually a biological mechanism.

If you keep seeing your child as wonderful, they eventually become wonderful.

That’s just how it works.

So while step-parents might want to call things out more directly, I think they should largely focus on relationship-building rather than discipline.

Your personal boundaries still matter—so, for example, stepkids can’t swear at you, disrespect you, or cross major lines.

But the big discipline conversations should be handled by the biological parent.

The person who loves them the most should be the one leading the discipline.

That’s usually the birth parent.

Laura Jenkins
The old connection before correction.

Now, for parents of both biological and stepchildren, creating a sense of fairness and inclusion can be really challenging.

Any advice on nurturing healthy sibling bonds and minimising some of that expected rivalry in blended families?

Nathan Wallis
Oh, sibling rivalry!

I have no perfect answers for this one—my two youngest were probably the worst for it!

I tried so many different strategies.

But one of the biggest things? Let them have a voice in the solution.

If there’s a recurring problem, don’t just solve it for them.

Hold a family meeting—but not in the heat of the moment.

Say, “Alright, we’re going to talk about this in two days—think about how you’d like to resolve it.”

When they have time to think about it, they come to the table more maturely and have better discussions.

Also, reward positive communication.

One thing I did that worked?

I banned negative statements at the dinner table.

If anyone made a negative comment about someone else, they had to do the dishes.

Laura Jenkins
Oh, I love that!

Nathan Wallis
And on the flip side, I rewarded positive statements.

If they said something genuinely nice about a sibling—not forced—they got a small reward.

For example:

• “You get 30 minutes of PlayStation time.”

Let me tell you—my son struggled with this.

It nearly killed him to say something nice about his sister!

But eventually, he learned.

And it worked! Over time, it actually shifted the tone in our home.

Laura Jenkins
I love the positive reward idea.

We often hear about punishments, like “Right, you’re on dishes duty if you don’t behave”—but flipping it to rewarding kindness is so much more effective.

Nathan Wallis
Exactly. But it has to be sincere.

You know when they’re just saying, “Oh, I like your dress,” to get the reward.

The real success comes when they say something meaningful, like:

“I think you handled that situation at school really well today. I was proud of you.”

That’s huge.

Laura Jenkins
Yeah, I love that one.

Alright, finally, Nathan—what are some common misconceptions parents might have about their children’s emotional adjustment in a blended family?

And how can parents better support their kids through these transitions?

Nathan Wallis
One of the biggest misconceptions?

Thinking kids will just “go along with it” and be happy because the parents are happy.

That’s unrealistic.

Yes, some kids adjust easily—but others need time, space, and validation.

Another misconception?

Thinking that just because two kids are the same age and gender, they’ll automatically get along.

It doesn’t work like that.

Just because you have two 13-year-old girls doesn’t mean they’re going to be best friends overnight.

You have to allow those relationships to develop organically.

One great strategy? Introduce the kids in neutral environments.

I know one family who wanted to blend households, so they took the kids on a holiday together first.

The kids weren’t in each other’s space, they had their own rooms, and they got to bond naturally in a fun setting.

You don’t have to go on a big expensive trip, but even something like meeting at a park can help make those first interactions feel less forced.

Laura Jenkins
Yeah, I like that one.

Are there any resources you’d recommend for parents looking to better understand children’s emotional regulation and how to manage these transitions?

Nathan Wallis
Yeah. I mean, my whole career has been about finding the “cheat sheet” version of parenting advice—because let’s be real, most parents aren’t going to read a 500-page book on child development.

So I try to simplify things into the most effective, fastest, and easiest strategies.

One of the best things I recommend? The Make Date.

If you search Nathan Wallis Make Date on YouTube, you’ll find a full explanation.

But the short version is this:

• Once a week, for 10 minutes, you set aside one-on-one time with your child.
• For the first three weeks, it might feel like nothing’s happening.
• But by the fourth week, you’ll start having deep, meaningful conversations.

It’s simple, but it changes everything.

It strengthens communication, builds trust, and helps kids feel secure—especially in a blended family where they might be adjusting to new relationships.

And once they know it’s a predictable, recurring thing, they start using that time to bring up the things that really matter to them.

Laura Jenkins
That’s such a simple but powerful idea!

And what else?

Nathan Wallis
The second big one? Validation.

Especially with teenage girls—but really, it applies to all kids.

As parents, we tend to get defensive when kids say things like:

• “You made me feel ugly when you told me to put my jacket on.”
• “You embarrassed me in front of my friends.”

Our first instinct is to say:

• “That’s not what I meant!”
• “I wasn’t trying to do that!”

But here’s the thing: It doesn’t matter what you meant. It matters how they felt.

So instead of correcting them, just validate their experience.

Say something like:

• “I’m sorry you felt that way. That wasn’t my intention, but I can see how it came across that way.”

Teenagers, especially, live in a world that is 90% emotion.

And if you don’t speak to their emotion first, they won’t feel heard—and if they don’t feel heard, they won’t listen to you.

It’s that simple.

Laura Jenkins
That makes so much sense.

So, just to recap—if parents do nothing else, the two best strategies are:

1. Make Date: One-on-one time, 10 minutes a week, same time every week.
2. Validation: Reflect their emotion before you give advice.

Nathan Wallis
Exactly.

Those two things alone will completely change the way your child communicates with you.

It’s not just theory—it’s what actually works in real life.

And if you look at the teachers that all the kids confide in, or the one mum in the friend group that all the kids open up to—it’s always the same thing.

Those people are validating first, advising second.

So if you want kids who trust you, start there.

Laura Jenkins
I love it.

Two very simple but effective takeaways, Nathan.

Nathan Wallis
Yeah! And fast. We like fast.

Laura Jenkins
We do. We do, absolutely.

Well, Nathan, thank you so much for your time today.

I have learned a lot and really enjoyed our conversation.

For anyone who’d like to connect with you, Nathan—where can they find you?

Nathan Wallis
Yeah, my website is nathanwallis.com.

And I’m also on Facebook, Instagram, and all of that sort of stuff.

Laura Jenkins
Wonderful!

Well, we’ll link to all of that in the show notes.

But once again—thank you so much, Nathan!

Nathan Wallis
Okay, cheers!

Laura Jenkins
I absolutely loved this conversation with Nathan, and I hope you did too.

One of my biggest takeaways?

Predictability is everything for a child’s brain.

It’s such a simple yet powerful reminder of how consistency helps kids feel safe and secure.

I also really loved Nathan’s point that even if you only have a few minutes, that regular one-on-one time is crucial.

It’s not about quantity—it’s about repetition and making sure kids feel seen, heard, and valued.

Thanks again for tuning in, and I’ll catch you next time!

Thanks for listening to In The Blend!

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