Being a toddler in a royal Windsor household doesn't mean the usual patterns of behaviour associated with a new baby coming into the home won't apply - even if that home is a little larger than average.

Prince George will probably be very excited at first about the arrival of the new baby. Most young children are intrigued by a new arrival and George may experience a sense of curiosity depending on how much exposure to babies he has had in the past.

Yet the initial effects may be short lived and once George realises that his brother or sister is actually staying with the family, he might think a little differently about the new addition to the family - for a while at least. The attention toddlers pay initially can fade rapidly, replaced by disinterest as they realise babies don't do very much at all, except make a noise and attract a lot of attention.

And that's where problems can often really begin if parents aren't careful. Kate and William appear pretty level headed and will be careful to support George while also giving the time needed to the new baby - plus of course they may well have an increase in help, paid or otherwise - but it isn't easy for anyone to get the balance right. Clearly the attention on the family will shift for a while onto the new baby, potentially even more so if it's a girl.

Young children can often experience a sense of loss, accompanied sometimes by a sense of abandonment. George may feel resentment toward his mother and sibling, leading to ' bad' behaviour, demonstrated by misbehaving, waking up in the night, becoming aggressive or regressing to an earlier developmental stage, all in a bid to bring the focus back to him. However, although this process is somewhat traumatic for first born children, it is usually transient.

George will adjust to having a sibling, especially if, over time, his parents nudge the family dynamic to share out the attention paid to each child, something many parents do naturally once the initial excitement dies down. It isn't uncommon for parents to struggle to regain this balance, however, and poor behaviour can become entrenched if an older child's need for attention and engagement isn't understood and acted upon over the first few weeks.

The relationship between the siblings is a key part of any family dynamic and the sex of the new arrival is clearly an important factor in this. A girl will again present different challenges for the royal couple to accommodate, privately for George and publicly in terms of the level of media interest.

For George the whole transition period may be difficult, but in time he should learn that the new sibling is not his replacement but rather an addition to the family unit. William and Kate clearly demonstrate sensitive and responsive parenting, so it is likely that George will fully embrace his 'big brother' role as he will be encouraged to understand that his place in the family - both as a single unit and at a wider level - has not changed, but has simply been redefined.