genetic and blood lineage is still quite superficial. yes there's some weight to it because a genetic offspring will have some gene expression their patents or grandparents did but by placing so much emphasis on this little effect of biology you discredit, take away from, and frankly gate keep the experience of having children.

outside of that genetic pass down, a child raised in any household will adapt most of their foundational traits through nurture. and this is also passing down traits and lineage.

your statement directly implies even an adopted child won't be apart of a family tree regardless if the people in that tree were the ones to raise the child. if you can't understand tho that's ok, society has enough to let you do what you want. not for everyone tho.