Australia 
USA 
Welcoming a new baby is magical for everyone, except sometimes the firstborn, who can feel as if their whole world has been flipped upside-down overnight. Studies show many older children wobble with jealousy, clinginess or the odd tantrum in those early weeks. When you shine a light on their upgraded title, the BIGGEST, what could feel like a demotion becomes a badge of honour.
The psychology of sibling jealousy
Why does jealousy pop up?
- Survival instincts – little ones worry they now have to share your hugs, snacks and story time.
- Age and stage – toddlers can’t quite say, “I miss one-to-one time,” so they act it out instead.
- Household shake-up – broken sleep, visitors and nappy changes turn familiar routines inside-out.
A Family Transitions Study that followed 241 families found nearly two in five firstborns became extra clingy or a bit aggressive in the first month after baby arrived, but those behaviours melted away within a year when parents involved them positively. Left to fester, jealousy can linger, yet it absolutely doesn’t have to.
Why calling them “biggest” beats simply “big”
Boosts confidence - children who see themselves as helpers score higher for self-worthy and empathy.
Cuts down rivalry - positive labelling nudges focus from competition to teamwork.
Sparks nurturing skills - once the role is named, most older siblings naturally slide into gentle teacher-and-carer mode.
5 Easy ways to celebrate your “biggest”
Gift a keepsake – A special book such as You’re The Biggest or a shiny badge marks the moment and says, “This is your day too.”
Ring-fence one-to-one time – Even ten minutes of LEGO, bubbles or bedtime reading works wonders.
Use empowering words – Swap “Be careful” for “You’re brilliant at keeping baby safe” to build competence.
Let them help – Fetching wipes, choosing a babygrow or shaking the rattle makes them feel needed.
Celebrate publicly – Encourage grandparents and nursery staff to greet them with “Hello, Biggest!” Social cheers amplify the message.
Spotlight on You’re The Biggest
Our bestselling picture book was written for this very moment. Each page invites your child to show baby the ropes, from roaring like a lion to perfecting high-fives. Parents tell us their little ones reach for it whenever they need a gentle reminder that their place in the family is rock-solid. Pair it with a matching badge or tee and the title travels everywhere, not just at story time.
Frequently asked questions
Will all this praise pile on pressure?
Not if you balance the high-fives with permission to feel wobbly. A simple “It’s okay to miss our old routine” takes the weight off their shoulders.
My toddler is still acting out, help!
Name the feeling (“You wish Mummy could cuddle you right now”) and hand them a mini helper task. Most flare-ups settle in a few weeks with steady consistency.
Take-home message
A little jealousy is perfectly normal, but it’s not a life sentence. Celebrate your child’s promotion to biggest and you’ll rewrite the family story from rivalry to teamwork, a story that lasts long after the newborn phase.
“When parents back their firstborn’s new identity, warmth can outshine rivalry by early childhood.” – Child & Family Research Review, 2024
Ready to help your rising star shine? Explore You’re The Biggest and other sibling-celebration gifts in our New Arrivals collection.
Written in UK English, because love, like spelling, comes in all flavours.
