Who's Your Daddy? No, Really ... Who?

In today's screwed up legal system, it has become commonplace for parents that give their children up for adoption to later regain their parental rights many years later ... after all the hard work is done. I have friends who are currently seeking to adopt from Russia, partly because all legal decisions made regarding adoptions are final. I fail to understand the logic of a birth parent re-introducing themselves into a child's life after the kid has been raised by, and bonded to the adoption parents ... is merely sharing DNA that important? What about the rights of the family who took in a stranger as raised them as their own? Doesn't that selfless act of generosity and love account for anything? The court system is so hellbent on reinforcing family structure, that it is willing to rip others apart for the sake of reuniting strangers.