Prince William (a fellow left-hander himself) has been reported as saying that he hopes his son George (third in line to be King of The United Kingdom) is left-handed as well “so he can be a brainbox”. There have been plenty of lefthanders in the Royal Family but until recently it was suppressed and they were forced to change. King George VI famously developed a stammer as a result, as portrayed in the the film “The King's Speech”.
Prince George is only just over a year old, so not giving obvious signals yet, but we know from our own children that they demonstrated a distinct hand preference from a very early age, so maybe William has noticed something.
There is certainly a stong history of King Georges being left-handed, with 3 of the last 5 being lefties.