Estates are generally passed down through the male lineage.
Bloodline could primarily be considered as the female lineage.

You get decide what bloodline you wish to specify – but it will commonly be different from your Estate (Birth Cert. Surname) name.

Bloodlines
Mitochondrial DNA (Maternal Line): Passed exclusively through the mother.
Y-Chromosome (Paternal Line): Passed exclusively through the father to male descendants.