I have a friend who grew up on Purto Ricco and her husband is from Peru .. 2 of their kids were born with black hair and 2 of their kids were born with blonde hair that eventually turned brown
Here's is another story ... I have a friend that had real blonde hair (like Jack Roberts) when he was little .. his hair is now jet black
The reason for me mentioning these things is because .. it is very possible for the Roberts kids hair will eventually turn dark as they get older
That's true and, like you said, really common. My husband is half Italian and had straight strawberry blonde hair when he was young. It's now very dark brown and curly. He showed me his kindergarten class picture and I couldn't even pick him out! LOL!
My dad (Polish) had ultra-blonde (think young Rick Schroeder) hair that turned dark brown as he got older.