It is not clear why Prince William is bald, but Prince Harry has lovely ginger locks. It is probably chance.
Prince William’s baldness is due to a common genetic condition called male pattern baldness or ‘androgenetic alopecia’. This condition affects many men and is caused by a combination of genetics and hormones.
From Prince Harry’s book ‘Spare’, he says,
I looked at William, maybe for the first time since we were boys, and observed his alarming baldness.”
Male pattern baldness is characterised by a gradual thinning of hair on the crown and temples of the head, eventually leading to baldness. William’s ‘baldness genes’ are likely to be predominantly inherited from his father, the late Prince Philip.
Summary
We have explained why is Prince William so bald and Prince Harry isn’t. Probably chance.