Answer:
For me, family is an emotional connection more than a heretitary lineage. The bond between a few people makes them family, not their blood. Being a parent/guardian is nothing more and nothing less than being the nurturing, cultivative figure in a child's life. This is why adoption is an option, because if "family" were restricted to only ancestral lineage, then those who have adopted children and adopted parents/guardians wouldn't be considered a family. Motherhood especially is based on the nurturing nature of a maternal figure. In nature, children often have bonds with their mothers, even if they aren't biological parents, because it is less a matter of who birthed them and more a matter of who cares for them.
When my parents give me advice, I take it more carefully than I would a stranger, or even someone else I trust, because my parents have put in so much time, energy, and resources into my survival and my thriving. Because of their efforts, I know I can trust them. Noone would waste time raising a child only to give them idiotic and/or destructive advice. So I take their advice, and I hold it dear more.
I hope this helps!