And the boys’ fathers don’t even know they exist. I wonder if the mother is still alive?
These days the adoption agency or whoever facilitates the adoption has to either make sure the father has voluntarily legally abandoned the child or had his parental rights terminated. If the mother claims she does not know who the father is a diligent search must be done to learn his identity and have him give up his rights or start the process to have them terminated.
It may be she knew who the fathers were but choose not to name them to avoid the hassle of having the consent to the adoption. She probably also figured they would be very hard to find even with a diligent search.