Stress that the child was not given up because of the circumstances of her conception, but because the mother could not care for her (which may have been partly because of the emotional trauma of the cirucumstances of the conception).
In early childhood: “It wasn’t a happy relationship. Your birthmother was scared. Sometimes your birthfather hadn’t respected her and had made her do things that hurt her. She didn’t want you around him, and she was too hurt by what had happened to take care of you herself, so she made an adoption plan that would keep you safe and give you loving parents.”
In elementary school: When a child is old enough to understand what sex is and that it is what creates a child, explain that people can use sex to make love, or sometimes they can just have sex without thinking, or that sometimes people use sex to make other people do what they want. People who do this aren’t able to take care of children safely.
For older children: I believe the experts’ opinion on telling around age 12 is especially important here, especially for boys. A child in the throes of hormones does not need to hear for the first time that his/her birthfather was incapable of controlling impulses. By telling a child earlier, at a time when self-esteem is greater that it typically is during adolescence, adoptive parents have more time to stress that our lives are not determined by fate but by choices.
Be aware that family or cultural pressure or a sense of shame may lead a birthmother to claim rape even if she did in fact consent to sex. Tell a child his birthfather committed rape only if you are absolutely sure this occurred.
For all children, parents must counter the idea the child may have that he or she “is not meant to, or has no right to, be here”. (See this related blog.) A parent’s beliefs about a Creator may be a great help here. Families may also stress that the child has given great joy to many and can, by his/her actions, be a great gift to the world.
Please see these related blogs:
Book Review: Making Sense of Adoption by Lois Ruskai Melina
Book Review: Real Parents, Real Children