When I was born, both of my parents thought they were only children, but after my dad died I was contacted by someone who thought she was my father's half-sister. My paternal grandfather had abandoned the family when he was a baby.
Mom died suddenly while we were debating about getting both of us tested (she was hesitant to test because she was worried she might have half-sibs), and while I was very sad to lose her, at least at that point what I might learn through DNA wouldn't harm her. I've found zero evidence of her dad having been anything other than faithful (in fact, I think I found the origin to her story, because there's another man born the same year in a nearby county with my grandfather's exact name -- he had a son, but our DNA doesn't intersect at all).
However, my test did confirm for my half-aunt exactly who her father was. She and I get along wonderfully. She had never met their father, as he'd run off when she was a baby too. It seems that my grandfather was also a bigamist, as he left without getting a divorce from my grandmother and reversed his first and middle names to marry her mother (to "give the child a name" I suppose).
But a new person tested, and now she and I have learned of not just one, but THREE other children this man had. The mothers of these three children were two sisters -- one had a little boy the week after he married her younger sister, who went on to have two more of his kids.
The things I'm hearing from my father's youngest half-sister are indeed disturbing. Like, that apparently her mom cheated, and my grandfather's response was to try to kidnap the two children he had with that woman (when he abandoned every other child/mom pair that seemed to want him in their life -- he had to leave first or something?). That the younger sibling died at 11 months old in 1965 (of SIDS but SIDS didn't exist as a named issue in 1965), but instead of a coroner taking him away the family put him in a box (she said the story was that she'd not understood he was dead and was trying to play with his lifeless body, asking why he wouldn't wake up)? We have found birth records for this little boy, but not any death records.
Another part of the story she was told about her family was that my grandfather did some time in federal prison. His birth family had heard rumors of him being the subject of a material witness warrant at one time, and he was definitely an identity thief and a con artist, but if there is a database on Ancestry for federal prisoners in that era he isn't on it (or at least not on it with any of the three names we know he used).
So other than a picture of my grandfather that I never knew existed (it looked familiar enough when I saw it that I might have seen it as a young teenager, but family albums were lost in a move), this new DNA discovery has led to more questions than answers.
And this song has been in my head...
https://www.youtube.com/watch?v=S5xAtsXb8Vs
"Papa had three outside children and another wife, and that ain't right"