How Important is Preserving Your Family Name? [POLL]

http://youtu.be/uNLdia5Mt10

I was adopted in my teens, and for the past few years I've been thinking about going back to my birth name.

But my son isn't convinced. He doesn't want to change his last name.

He's 21 and comfortable with the name he's always had. I've been trying to persuade him, however, that his birth name isn't really his lineage and that he should join me in taking our proper last name. He's the last in line with my family name and the only male child.

If he doesn't change his name, our line dies.

Isn't preserving your lineage worth maintaining your family name? Which one of us is right?