They're known for their modern approach to parenting, but it seems the Duke and Duchess of Cambridge are very traditional in other ways ... as revealed by photos of the family during public appearances.
Prince William always looks after Prince George while Kate Middleton takes care of Princess Charlotte.
The arrangement is certainly no coincidence, according to parenting expert Jasmine Peters who told the Daily Mail that it's all part of setting George up for his role as future King.
"Fathers are typically responsible for the disciplinary actions, redirection, protection and provision of the family," she explained.
"It is not uncommon to see a father with his son to set the foundation of what his role and responsibilities will be in life with a family. It is often believed that it takes a man to raise a boy to be a man. If you look at the pictures it clearly reflects this common belief."
She added that having boys with Dad and girls with Mum is actually a sign that William and Kate are instinctive and loving parents.
"Yes, it could reflect that Kate and William are traditional, but it also reflects the importance of the bond created between father and son and mother and daughter that they both treasure and hold dearly as responsible and loving parents," she explained.
"Children often equate their worth to the parent that looks like them.
"And any parent that understands how their bond will affect their child in the future when they become adults understands the importance of creating a strong bond early on in their childhood and youth."
She added that William and Kate clearly understand the responsibility they have to their children.
"Although these pictures can look a bit traditional, William and Kate may also understand the importance of a son bonding with his father and a daughter bonding with her mother," she said.
This goes beyond gender roles and extends into the creation of the very essence of a human - being able to share stories and experiences with someone that looks just like you.
"They realise the importance of bonding with them early on and training them up from their youth into adulthood, so establishing a solid foundation which is created early on in parent-child relationships."
Lucy Shrimpton, The Sleep Nanny and expert at The Baby Show added that George may naturally gravitate towards his father because he's the older child.
"The children are close in age and when the new baby depends heavily on Mum, it is natural for the toddler to gravitate towards dad who can provide more attention when mum is busy with the baby.
"If George has spent extra time with dad because mum has had her hands full with a new baby, they may have built a father-son bond that has stuck.
"I believe the same would have happened even if they had a girl first and then a boy or even two girls. I imagine you would still see the older sibling with dad more and the younger with mum at this sort of age.
This article was first published on Daily Mail and is republished here with permission.