I believe people are free to call themselves by whatever name they want. A parent's love for a child shouldn't change because their name changed. They're still family via bloodline is the key.
If this were not so then everyone with the same last name would be considered family! It's the bloodline not the name that counts.
In many ways choosing one's own last name is the ultimate sign of independence and taking charge of one's own life path.
Norma Jeane Mortenson and Marion Mitchell Morrison changed their names to Marilyn Monroe and John Wayne. I'm sure their families still loved and accepted them.
One shouldn't have to be a celebrity to be accepted with a name change.