True, there are many things you CAN do that have no legal standing.
Example: A man who is a joint owner of his house CAN "WILL" the house to his mistress, instead of his jt tenant wife. However, as he has no legal standing to give away something he is not legally entitled to, the house will become the sole property of the surviving joint tenant, regardless of the will. Reason being, he had no legal standing to will it in the first place, as the Jt. Tenant has survivorship rights.
I CAN sign a deed "quit claiming" YOUR house to someone else. That does not legally entitle that someone else to your house. I CAN sue you for something trivial. That does not mean I CAN win.
Adoptive parents ARE "real" parents. Sharing genes is not what makes you a "parent"!