This just makes me ill. It takes one egg (from a woman) and one sperm (from a man) to make a child. Children deserve to know their parentage.
Does a child really need to now that they are the product of a rape or that their birth parents are father and daughter? Sometimes adoption is a way to give a child a chance to overcome a horrible beginning, and privacy should not be thown out with the bathwater in order to avoid the perversion of the idea of mother and father.