Biology is not Family
Can we just get that out there?
Sure, many times biology is equivalent to family. Many - possibly even most - children are parts of family groups with their biological parents. But Western society - specifically that of the United States - needs to realize that it has a mythology surrounding biological families. It is a mythology - a model, if you will - that does not hold up under even the lightest load.
Currently, this prejudice towards biological families leads to a kind of institutional discrimination towards adoptive parents. It's easy to hear people talk about the "cost" of getting an adoption while discounting thier own hospital bills as "normal". These children are often objectified - usually not by the parents, but by people once removed. Friends, relatives, and acquaintances talk about "getting" a child as if they were merely objects. Therefore, let's quickly demolish the idea of biology as a special definition of family.
Biology does not connote some special "bond". Parents do not automatically recognize their biological newborns. We are predisposed (through socialization, probably) to see features similar to our own when we look at children we think of as ours. Quick real life examples: Depending on who has been looking, I either resemble my mom or my dad. My son - who is biologically related to neither my wife or I - has been compared to both of us at different times.
Further, biology does not guarantee any kind of special caregiving or affection. Every tale of a dumpster-dumped baby, every child with reactive-attachment disorder, every abused child begs otherwise. Clearly, being a sperm or egg donor - even carrying a child for nine months - does not confer some automatic soft-focus lens of "family".
But it's not enough to demolish a model. One must propose another.
So, I suggest this: A family is created by the mental and social self-identification of being part of a family. It is a recursive self-identifying phenomenon.
This explains both the idyllic families and the utterly neglectful dysfunctional ones. It explains unequal (and frequently abusive) relationships where one party has a self-identification that is exploited by the other. It explains both the higher rates of abuse in blended families (pointing to the need for aid in achieving that self-identification) and those instances where adoption and blended families work perfectly together.
S, my biological son, was neglected, emotionally abused, and probably suffered some physical abuse at the hands of his biological mother. He recieved care and kindness - in the face of his rage and mental illness - from his "step" mother... for longer than his birth mother was around. Calling the egg donor who gave birth to him the "real" mother is blasphemous and an insult to my wife.
Therefore, while biology may be highly correlational with "family", it *should never* be mistaken as the causal element.
(Side note: Yeah, this means that I have nothing against gay people adopting.)