Glad to help.
It’s a weird concept outside of inheritance - for example, a royal bloodline could end because the regent dies without children. Because the upstream follows the ruler, you might have to backtrack up the bloodline to find the next heritor, which you’d call a branch bloodline
But in modern life? It’s kinda pointless as a concept. We care about heredity and family, not bloodlines
No, let’s give them random privileges too. You get to drive in the HOV lane alone, you get a license made of metal, and you get to park in all handicap spaces except the closest to the entrance. And if you pay enough in taxes, you get an invite to the yearly pizza party with the president