OP here. Thank you all for your responses, please keep them coming.
Anonymous wrote:I would want to know. You wouldn't have the same health issues as the dad who raised you.
The dad and his family are pretty healthy, so the child will not be concerned about anything false positive. The bio father's family health is unknown anyway, since he is not in the picture and no one is in touch with him, and he has no desire to be contacted. The mom tried to discuss his family's side health story with him when she became pregnant, and he didn't answer any questions at that time. So if somebody reaches out to him 20 years later, it's very unlikely he would want to talk about anything and most likely will deny the entire story and fatherhood.