The Cousin-Mom
This one, however, is pretty strange, to say the least. The OP’s mom gave birth to them when she was just 16, so her uncle took them aboard and called them his own. Since the mom was still in the picture, the adoptive dad told the OP that their mom was actually a cousin.
The mom didn’t grow up to be the finest person in society, but the OP doesn’t hold anything against her. They know that the mom regrets giving them up, but she was just a kid herself when she gave birth! It’s nice to know that family has your back, even if it leads to strange situations in the future.